Tempered glass, tempered glass plate, and glass for tempering

ABSTRACT

A tempered glass has a compressive stress layer in a surface thereof, includes as a glass composition, in terms of mass %, 50 to 80% of SiO 2 , 10 to 30% of Al 2 O 3 , 0 to 6% of B 2 O 3 , 0 to 2% of Li 2 O, and 5 to 25% of Na 2 O, and is substantially free of As 2 O 3 , Sb 2 O 3 , PbO, and F.

TECHNICAL FIELD

The present invention relates to a tempered glass and a tempered glasssheet, and a glass to be tempered, and more particularly, to a temperedglass and a tempered glass sheet, and a glass to be tempered suitablefor a cover glass for a cellular phone, a digital camera, a personaldigital assistant (PDA), or a solar battery, or a glass substrate for adisplay, in particular, a touch panel display.

BACKGROUND ART

Devices such as a cellular phone, a digital camera, a PDA, a touch paneldisplay, a large-screen television, and contact-less power transfer showa tendency of further prevalence.

A tempered glass, which is produced by applying tempering treatment toglass through ion exchange treatment or the like, is used for thoseapplications (see Patent Literature 1 and Non Patent Literature 1).

In addition, in recent years, the tempered glass has been more and morefrequently used in exterior parts of, for example, digital signage,mice, and smartphones.

Characteristics required of the tempered glass include (1) highmechanical strength, (2) low cost, and (3) high dimensional accuracy. Indigital signage applications, a structure in which a plurality of panelsare linked together has been adopted in an increasing number of cases,and in association with this, a higher level of dimensional accuracy hasbeen demanded. Specifically, while a conventional dimensional tolerancehas been about ±4,000 ppm, a demand has arisen for a dimensionaltolerance of about ±1,000 ppm.

CITATION LIST Patent Literature

-   [PTL 1] JP 2006-83045 A

Non Patent Literature

-   [NPL 1] Tetsuro Izumitani et al., “New glass and physical properties    thereof,” First edition, Management System Laboratory. Co., Ltd.,    Aug. 20, 1984, p. 451-498

SUMMARY OF INVENTION Technical Problem

However, a tempered glass (glass to be tempered) is liable to undergo adimensional change between before and after tempering treatment. Thus,it is not easy to increase the dimensional accuracy of the temperedglass.

In addition, the tempering treatment is generally performed by immersingthe glass to be tempered in a high-temperature (for example, from 300 to500° C.) KNO₃ molten salt. Accordingly, the tempering treatment of alarge-size glass sheet to be tempered involves a problem in that theglass is liable to undergo breakage owing to a thermal shock when theglass to be tempered is immersed or when the tempered glass sheet istaken out. In order to solve the problem, it is conceivable to employ amethod involving preheating the glass sheet to be tempered beforeimmersion, or annealing the tempered glass sheet that has been takenout. However, such method requires a long period of time, and henceinvolves a risk that the manufacturing cost of the tempered glass sheetmay soar.

The present invention has been made in view of the above-mentionedcircumstances, and a technical object of the present invention is todevise a tempered glass, tempered glass sheet, and glass to be temperedthat have high ion exchange performance, hardly undergo a dimensionalchange before and after tempering treatment, and have high thermal shockresistance.

Solution to Problem

The inventors of the present invention have made various studies andhave consequently found that the technical object can be achieved bystrictly controlling the glass composition. Thus, the finding isproposed as the present invention. That is, a tempered glass of thepresent invention has a compressive stress layer in a surface thereof,comprises as a glass composition, in terms of mass %, 50 to 80% of SiO₂,10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, and 5 to 25% ofNa₂O, and is substantially free of As₂O₃, Sb₂O₃, PbO, and F. Herein, thegist of the phrase “substantially free of As₂O₃” resides in that As₂O₃is not added positively as a glass component, but contamination withAs₂O₃ as an impurity is allowable. Specifically, the phrase means thatthe content of As₂O₃ is less than 0.1 mass %. The gist of the phrase“substantially free of Sb₂O₃” resides in that Sb₂O₃ is not addedpositively as a glass component, but contamination with Sb₂O₃ as animpurity is allowable. Specifically, the phrase means that the contentof Sb₂O₃ is less than 0.1 mass %. The gist of the phrase “substantiallyfree of PbO” resides in that PbO is not added positively as a glasscomponent, but contamination with PbO as an impurity is allowable.Specifically, the phrase means that the content of PbO is less than 0.1mass %. The gist of the phrase “substantially free of F” resides in thatF is not added positively as a glass component, but contamination withFas an impurity is allowable. Specifically, the phrase means that thecontent of F is less than 0.1 mass %.

The introduction of given amounts of Al₂O₃ and the alkali metal oxidesinto the glass composition can enhance ion exchange performance, thermalshock resistance, and devitrification resistance. Further, thedevitrification resistance can be enhanced by regulating the contentsand content ratios of Al₂O₃, B₂O₃, and alkaline earth metal oxides.

Second, the tempered glass of the present invention preferably comprisesas a glass composition, in terms of mass %, 50 to 80% of SiO₂, 10 to 30%of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0 to 25% ofNa₂O, and 0 to 2% of SrO.

Third, the tempered glass of the present invention preferably comprisesas a glass composition, in terms of mass %, 50 to 76% of SiO₂, more than16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0to 25% of Na₂O, 0 to 2% of SrO, and 0 to 4.5% of TiO₂.

Fourth, the tempered glass of the present invention preferably comprisesas a glass composition, in terms of mass %, 50 to 76% of SiO₂, more than16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0to 25% of Na₂O, 0 to 2% of SrO, 0 to 0.5% of TiO₂, and 0 to 4% of ZrO₂.

Fifth, the tempered glass of the present invention preferably comprisesas a glass composition, in terms of mass %, 50 to 76% of SiO₂, more than16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0to 25% of Na₂O, 0 to 2% of SrO, 0 to 0.5% of TiO₂, 0 to 4% of ZrO₂, and0 to 1% of P₂O₅, and preferably has a molar ratio(MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.60. Herein, the term“MgO+CaO+SrO+BaO” refers to the total amount of MgO, CaO, SrO, and BaO.In addition, the term “Al₂O₃+B₂O₃” refers to the total amount of Al₂O₃and B₂O₃.

Sixth, the tempered glass of the present invention preferably comprisesas a glass composition, in terms of mass %, 50 to 76% of SiO₂, more than16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to less than 1.0% of Li₂O, morethan 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 0.5% of TiO₂, 0 to 2% ofZrO₂, 0.2 to 3% of SnO₂, and to 1% of P₂O₅, and preferably has a molarratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.55.

Seventh, the tempered glass of the present invention preferablycomprises as a glass composition, in terms of mass %, 50 to 73% of SiO₂,more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to less than 1.0% ofLi₂O, more than 7.0 to 25% of Na₂O, 10 to 30% of Li₂O+Na₂O+K₂O, 0 to 4%of CaO, 0 to 2% of SrO, 0 to 0.5% of TiO₂, 0 to 2% of ZrO₂, 0.2 to 3% ofSnO₂, and 0 to 1% of P₂O₅, and preferably has a molar ratio(MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.55. Herein, the term“Li₂O+Na₂O+K₂O” means the total amount of Li₂O, Na₂O, and K₂O.

Eighth, in the tempered glass of the present invention, it is preferredthat a compression stress value of the compression stress layer be 300MPa or more and 1,200 MPa or less, and a thickness of the compressionstress layer be 10 μm or more and 60 μm or less. Herein, the“compression stress value of the compression stress layer” and the“thickness of the compression stress layer” refer to values calculatedfrom the number of interference fringes and intervals therebetween, theinterference fringes being observed when a sample is observed using asurface stress meter (for example, FSM-6000 manufactured by TOSHIBACORPORATION).

Ninth, the tempered glass of the present invention preferably has aliquidus temperature of 1,200° C. or less. Herein, the term “liquidustemperature” refers to a temperature at which crystals of glass aredeposited after glass powder that passes through a standard 30-meshsieve (sieve opening: 500 μm) and remains on a 50-mesh sieve (sieveopening: 300 μm) is placed in a platinum boat and then kept for 24 hoursin a gradient heating furnace.

Tenth, the tempered glass of the present invention preferably has aliquidus viscosity of 10^(4.0) dPa·s or more. Herein, the term “liquidusviscosity” refers to a value obtained through measurement of a viscosityof glass at the liquidus temperature by a platinum sphere pull upmethod.

Eleventh, the tempered glass of the present invention preferably has atemperature at 10^(4.0) dPa·s of 1,300° C. or less. Herein, the phrase“temperature at 10^(4.0) dPa·s” refers to a value obtained throughmeasurement by a platinum sphere pull up method.

Twelfth, the tempered glass of the present invention preferably has athermal expansion coefficient in a temperature range of from 25 to 380°C. of 100×10⁻⁷/° C. or less. Herein, the phrase “thermal expansioncoefficient in a temperature range of from 25 to 380° C.” refers to avalue obtained by measuring an average thermal expansion coefficientwith a dilatometer.

Thirteenth, a tempered glass sheet of the present invention comprisesthe tempered glass.

Fourteenth, a tempered glass sheet of the present invention is atempered glass sheet having a length dimension of 500 mm or more, awidth dimension of 300 mm or more, and a thickness of from 0.5 to 2.0mm, having a compression stress value of a compression stress layer of300 MPa or more and 1,200 MPa or less and a thickness of the compressionstress layer of 10 μm or more and 60 μm or less, and being subjected totempering treatment so as to have a dimensional change rate S betweenbefore and after tempering treatment of from −1,000 ppm to +1,000 ppm.Herein, the “dimensional change rate S between before and aftertempering treatment” refers to a value obtained by measuring a lengthdimension Lb before tempering treatment and a length dimension La aftertempering treatment, and then performing calculation by substituting thelength dimensions into the following equation:

S=1,000,000×(La−Lb)/Lb.

Fifteenth, the tempered glass sheet of the present invention preferablyhas a Young's modulus of 65 GPa or more.

Sixteenth, the tempered glass sheet of the present invention preferablyhas a fictive temperature Tf of 500° C. or more. Herein, the “fictivetemperature Tf” is an indicator for the molecular structure of glassreflecting thermal history during the cooling and solidification of aglass melt. Its value increases as the cooling is performed morerapidly, and lowers as the cooling is performed more slowly. Ameasurement method for the fictive temperature If is described below. Asample is kept at a temperature equal to or higher than its strain pointfor a sufficient period of time (for example, 24 hours), then rapidlycooled by, for example, being immediately brought into contact with ametal sheet, and measured for its dimensional change. When the sample iskept at a temperature T1 higher than the fictive temperature Tf, thedimensional change shows a positive value ΔL1, and when the sample iskept at a temperature T2 lower than the fictive temperature Tf, thedimensional change shows a negative value ΔL2. In the case where T1-T2is from 0 to 20° C., the Tf can be determined from the followingequation.

Tf=(T2×ΔL1−T1×ΔL2)/(ΔL1−ΔL2)

Seventeenth, the tempered glass sheet of the present invention ispreferably formed by an overflow down-draw method. Herein, the “overflowdown-draw method” refers to a method comprising causing a molten glassto overflow from both sides of a heat-resistant forming trough, andsubjecting the overflowing molten glasses to down-draw downward whilethe molten glasses are joined at the lower end of the forming trough, tothereby manufacture a glass sheet. In the overflow down-draw method,surfaces that are to serve as the surfaces of the glass sheet are formedin a state of free surfaces without being brought into contact with thesurface of the forming trough. Accordingly, a glass sheet havingsatisfactory surface quality in an unpolished state can be manufacturedat low cost.

Eighteenth, the tempered glass sheet of the present invention ispreferably cut at a position spaced apart downwardly by 1,000 mm or morefrom a lower end of a forming trough used in the overflow down-drawmethod.

Nineteenth, the tempered glass sheet of the present invention ispreferably used for a touch panel display.

Twentieth, the tempered glass sheet of the present invention ispreferably used for a cover glass for a cellular phone.

Twenty-first, the tempered glass sheet of the present invention ispreferably used for a cover glass for a solar battery.

Twenty-second, the tempered glass sheet of the present invention ispreferably used for a protective member for a display.

Twenty-third, a tempered glass sheet of the present invention is atempered glass sheet having a length dimension of 500 mm or more, awidth dimension of 300 mm or more, and a thickness of from 0.3 to 2.0mm, comprising as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, 5 to 25% ofNa₂O, 10 to 30% of Li₂O+Na₂O+K₂O, 0 to 2% of SrO, 0 to less than 0.50%of TiO₂, 0 to 4% of ZrO₂, 0.2 to 3% of SnO₂, and 0 to 1% of P₂O₅, havinga molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.60, beingsubstantially free of As₂O₃, Sb₂O₃, PbO, and F, having a compressionstress value of a compression stress layer of 300 MPa or more and 1,200MPa or less, a thickness of the compression stress layer of 10 μm ormore and 60 μm or less, a liquidus temperature of 1,200° C. or less, athermal expansion coefficient in a temperature range of from 25 to 380°C. of 100×10⁻⁷ or less, a Young's modulus of 65 GPa or more, and afictive temperature Tf of 500° C. or more, and being subjected totempering treatment so as to have a dimensional change rate S betweenbefore and after tempering treatment of from −1,000 ppm to +1,000 ppm.

Twenty-fourth, a glass to be tempered of the present invention comprisesas a glass composition, in terms of mass %, 50 to 80% of SiO₂, 10 to 30%of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, and 5 to 25% of Na₂O, andbeing substantially free of As₂O₃, Sb₂O₃, PbO, and F.

Twenty-fifth, a glass to be tempered of the present invention has adimensional change rate S between before and after tempering treatment(immersion in a KNO₃ molten salt at 440° C. for 6 hours) of from −1,000ppm to +1,000 ppm. It should be noted that as the KNO₃ molten salt,there is used one having no history of being used.

Twenty-sixth, the glass to be tempered of the present inventionpreferably has a fictive temperature Tf of 500° C. or more.

Advantageous Effects of Invention

The tempered glass of the present invention has high ion exchangeperformance. Accordingly, even when ion exchange treatment is performedfor a short period of time, the compression stress value of itscompression stress layer increases and the compression stress layer isformed so as to reach a deep portion. As a result, its mechanicalstrength is enhanced, and a variation in mechanical strength reduces.

In addition, the tempered glass of the present invention is excellent indenitrification resistance, and hence can be efficiently formed into ashape by the overflow down-draw method. It should be noted thataccording to the overflow down-draw method, a glass sheet having a largesize and a small thickness can be formed in a large amount.

Further, the tempered glass of the present invention has a low thermalexpansion coefficient, and hence the time required for preheating beforetempering treatment and/or the time required for annealing aftertempering treatment can be shortened. In addition, the tempered glass ofthe present invention has a high Young's modulus and a high fictivetemperature Tf, and hence the dimensional change between before andafter tempering treatment can be reduced.

DESCRIPTION OF EMBODIMENTS

A tempered glass of the present invention has a compression stress layerin a surface thereof. A method of forming the compression stress layerin the surface includes a physical tempering method and a chemicaltempering method. The tempered glass of the present invention ispreferably produced by the chemical tempering method.

The chemical tempering method is a method involving introducing alkaliions each having a large ion radius into the surface of glass by ionexchange treatment at a temperature equal to or lower than a strainpoint of the glass. When the chemical tempering method is used to form acompression stress layer, the compression stress layer can be properlyformed even in the case where the thickness of the glass is small. Inaddition, even when a tempered glass is cut after the formation of thecompression stress layer, the tempered glass does not easily breakunlike a tempered glass produced by applying a physical tempering methodsuch as an air cooling tempering method.

The following description shows the reason why the content range of eachcomponent in the tempered glass of the present invention is controlledin the above-mentioned range. It should be noted that in the descriptionof the content range of each component, the expression “%” means “mass%” unless otherwise specified.

SiO₂ is a component that forms a network of glass, and the content ofSiO₂ is from 50 to 80%, preferably from 55 to 76%, more preferably from55 to 75%, more preferably from 55 to 73%, more preferably from 55 to72%, more preferably from 56 to 69%, particularly preferably from 57 to67%. When the content of SiO₂ is too small in glass, vitrification doesnot occur easily, the thermal expansion coefficient becomes too high,and the thermal shock resistance easily lowers. On the other hand, whenthe content of SiO₂ is too large in glass, the meltability andformability easily lower, and the thermal expansion coefficient becomestoo low, with the result that it becomes difficult to match the thermalexpansion coefficient with those of peripheral materials.

Al₂O₃ is a component that enhances the ion exchange performance of glassand a component that enhances the strain point or Young's modulus, andthe content of Al₂O₃ is from 10 to 30%. When the content of Al₂O₃ is toosmall in glass, the ion exchange performance may not be exhibitedsufficiently. Thus, the lower limit range of Al₂O₃ is preferably 12% ormore, more preferably 13% or more, more preferably 14% or more, morepreferably 15% or more, more preferably 15.5% or more, more preferablymore than 16.0%, more preferably 16.1% or more, more preferably 16.3% ormore, more preferably 16.5% or more, more preferably 17.1% or more, morepreferably 17.5% or more, more preferably 18% or more, particularlypreferably 18.5% or more. On the other hand, when the content of Al₂O₃is too large in glass, devitrified crystals are easily deposited in theglass, and it becomes difficult to form a glass sheet by an overflowdown-draw method or the like. In particular, when a glass sheet isformed by an overflow down-draw method through use of a forming troughof alumina, a devitrified crystal of spinel is easily deposited at aninterface between the glass sheet and the forming trough of alumina.Further, the thermal expansion coefficient of the glass becomes too low,and it becomes difficult to match the thermal expansion coefficient withthose of peripheral materials. In addition, acid resistance also lowers,which makes it difficult to apply the tempered glass to an acidtreatment step. Further, viscosity at high temperature increases, andthe meltability easily lowers. Thus, the upper limit range of thecontent of Al₂O₃ is preferably 28% or less, more preferably 26% or less,more preferably 24% or less, more preferably 23.5% or less, morepreferably 22% or less, more preferably 21% or less, more preferably 20%or less, particularly preferably 19% or less. It should be noted that inthe case where high importance is placed on mechanical strength, forexample, in the case where tempering treatment is performed aftercutting into a cover glass shape and polishing, it is preferred toincrease the content of Al₂O₃ to the extent possible by sacrificing acidresistance to some degree. In that case, the lower limit range of thecontent of Al₂O₃ is preferably 16% or more, more preferably 17% or more,more preferably 18% or more, more preferably 18.5% or more, morepreferably 19% or more, more preferably 20% or more, more preferably 21%or more, more preferably 22% or more, particularly preferably 23% ormore. The upper limit range of the content of Al₂O₃ is preferably 30% orless, more preferably 29% or less, more preferably 27% or less, morepreferably 26% or less, more preferably 25.5% or less, particularlypreferably 25% or less.

B₂O₃ is a component that lowers the viscosity at high temperature anddensity of glass, stabilizes the glass for a crystal to be unlikelyprecipitated, and lowers the liquidus temperature of the glass. Thelower limit range of the content of B₂O₃ is preferably 0% or more, morepreferably 0.01% or more, more preferably 0.05% or more, more preferably0.1% or more, particularly preferably 0.4% or more. However, when thecontent of B₂O₃ is too large, through ion exchange, coloring on thesurface of glass called weathering may occur, water resistance maylower, and the thickness of a compression stress layer is liable todecrease. Thus, the upper limit range of the content of B₂O₃ ispreferably 6% or less, more preferably 5% or less, more preferably 4% orless, more preferably 3.95% or less, more preferably 3% or less, morepreferably 2% or less, particularly preferably less than 2.0%.

Li₂O is an ion exchange component and is a component that lowers theviscosity at high temperature of glass to increase the meltability andthe formability, and increases the Young's modulus. Further, Li₂O has agreat effect of increasing the compression stress value of glass amongalkali metal oxides, but when the content of Li₂O becomes extremelylarge in a glass system containing Na₂O at 7% or more, the compressionstress value tends to lower contrarily. Further, when the content ofLi₂O is too large in glass, the liquidus viscosity lowers, easilyresulting in the denitrification of the glass, and the thermal expansioncoefficient becomes too high, with the result that the thermal shockresistance lowers and it becomes difficult to match the thermalexpansion coefficient with those of peripheral materials. In addition,the viscosity at low temperature of the glass becomes too low, and thestress relaxation occurs easily, with the result that the compressionstress value lowers contrarily in some cases. Thus, the upper limitrange of the content of Li₂O is from 0 to 2%, and is preferably from 0to 1.7%, more preferably from 0 to 1.5%, more preferably from 0 to 1%,more preferably from 0 to less than 1.0%, more preferably from 0 to0.5%, more preferably from 0 to 0.3%, more preferably from 0 to 0.1%,particularly preferably from 0 to 0.05%.

Na₂O is an ion exchange component and is a component that lowers theviscosity at high temperature of glass to increase the meltability andformability. Na₂O is also a component that improves the devitrificationresistance of glass. When the content of Na₂O is too small in glass, themeltability lowers, the thermal expansion coefficient lowers, and theion exchange performance is liable to lower. Thus, the content of Na₂Ois 5% or more, and the lower limit range of the content of Na₂O is 7% ormore, preferably more than 7.0%, more preferably 8% or more, morepreferably 9% or more, more preferably 10% or more, more preferably 11%or more, more preferably 12% or more, more preferably 13% or more, morepreferably 13.8% or more, particularly preferably 14% or more. On theother hand, when the content of Na₂O is too large in glass, the thermalexpansion coefficient becomes too high, with the result that the thermalshock resistance lowers, and it becomes difficult to match the thermalexpansion coefficient with those of peripheral materials. Further, thestrain point lowers excessively, and the glass composition loses itscomponent balance, with the result that the devitrification resistancelowers contrarily in some cases. Thus, the content of Na₂O is 25% orless, and the upper limit range of the content of Na₂O is preferably 23%or less, more preferably 21% or less, more preferably 19% or less, morepreferably 17% or less, more preferably 16.3% or less, more preferably16% or less, particularly preferably 15% or less.

For example, the following components other than the components may beadded.

K₂O is a component that promotes ion exchange and is a component thatallows the thickness of a compression stress layer to be easily enlargedamong alkali metal oxides. K₂O is also a component that lowers theviscosity at high temperature of glass to increase the meltability andformability. K₂O is also a component that improves devitrificationresistance. However, when the content of K₂O is too large, the thermalexpansion coefficient of glass becomes too large, the thermal shockresistance of the glass lowers, and it becomes difficult to match thethermal expansion coefficient with those of peripheral materials.Further, the strain point lowers excessively, and the glass compositionloses its component balance, with the result that the devitrificationresistance tends to lower contrarily. Thus, the upper limit range of thecontent of K₂O is preferably 10% or less, more preferably 9% or less,more preferably 8% or less, more preferably 7% or less, particularlypreferably 6% or less. It should be noted that when K₂O is added, theaddition amount is preferably 0.1% or more, more preferably 0.5% ormore, more preferably 1% or more, more preferably 1.5% or more,particularly preferably 2% or more. In addition, when the addition ofK₂O is avoided as much as possible, the content of K₂O is preferablyfrom 0 to 1%, more preferably from 0 to less than 1.0%, particularlypreferably from 0 to 0.05%.

When the content of Li₂O+Na₂O+K₂O is too small in glass, the ionexchange performance or the meltability is liable to decrease. Thus, thelower limit range of the content of Li₂O+Na₂O+K₂O is preferably 10% ormore, more preferably 11% or more, more preferably 12% or more, morepreferably 13% or more, more preferably 14% or more, more preferably14.5% or more, more preferably 15% or more, more preferably 15.5% ormore, particularly preferably 16% or more. On the other hand, when thecontent of Li₂O+Na₂O+K₂O is too large in glass, the thermal expansioncoefficient becomes too high, with the result that the thermal shockresistance lowers and it becomes difficult to match the thermalexpansion coefficient with those of peripheral materials. In addition,the strain point lowers excessively, and the glass composition loses itscomponent balance, with the result that the denitrification resistancetends to lower contrarily. Thus, the upper limit range of the content ofLi₂O+Na₂O+K₂O is preferably 30% or less, more preferably 27% or less,particularly preferably 25% or less.

MgO is a component that reduces the viscosity at high temperature ofglass to enhance the meltability and formability, and increases thestrain point and Young's modulus, and is a component that has a greateffect of enhancing the ion exchange performance among alkaline earthmetal oxides. Thus, the content of MgO is preferably from 0 to 10%. Inthis case, the lower limit range of the content of MgO is preferably 0%or more, more preferably 0.5% or more, more preferably 1% or more, morepreferably 1.2% or more, more preferably 1.3% or more, particularlypreferably 1.4% or more. However, when the content of MgO is too largein glass, the density and thermal expansion coefficient easily increase,and the devitrification of the glass tends to occur easily. Particularlywhen a glass sheet is formed by an overflow down-draw method using aforming trough of alumina, a devitrified crystal of spinel is easilydeposited at an interface with the forming trough of alumina. Thus, theupper limit range of the content of MgO is preferably 9% or less, morepreferably 8% or less, more preferably 7% or less, more preferably 6% orless, more preferably 5% or less, more preferably 4% or less, morepreferably 3.5% or less, more preferably 3% or less, more preferably2.5% or less, more preferably 2.4% or less, more preferably 2.3% orless, particularly preferably 2.2% or less.

The mass ratio B₂O₃/MgO is preferably from 0.01 to 5, more preferablyfrom 0.01 to 3.5, more preferably from 0.01 to 2.2, particularlypreferably from 0.01 to 1.5. With this, the viscosity at hightemperature and the devitrification resistance can be easily madeproper.

The lower limit value of the molar ratio (3MgO+Al₂O₃)/Na₂O is preferably0.0 or more, more preferably 0.5 or more, more preferably 0.6 or more,more preferably 0.7 or more, more preferably 0.8 or more, morepreferably 0.9 or more, particularly preferably 1.0 or more. The upperlimit value of the molar ratio (3MgO+Al₂O₃)/Na₂O is preferably 2.5 orless, more preferably 2.0 or less, more preferably 1.9 or less, morepreferably 1.8 or less, more preferably 1.7 or less, more preferably 1.6or less, more preferably 1.5 or less, particularly preferably 1.4 orless. With this, when a glass sheet is formed by an overflow down-drawmethod using a forming trough of alumina, a devitrified crystal ofspinel is hardly deposited at an interface with the forming trough ofalumina.

CaO has greater effects of reducing the viscosity at high temperature ofglass to enhance the meltability and formability and increasing thestrain point and Young's modulus without involving a reduction indenitrification resistance as compared to other components. However,when the content of CaO is too large in glass, the density and thermalexpansion coefficient increase, and the glass composition loses itscomponent balance, with the result that the glass is liable to denitrifycontrarily, the ion exchange performance lowers, and the deteriorationof an ion exchange solution tends to occur easily. Thus, the content ofCaO is preferably from 0 to 6%, more preferably from 0 to 5%, morepreferably from 0 to 4%, more preferably from 0 to 3.5%, more preferablyfrom 0 to 3%, more preferably from 0 to 2%, more preferably from 0 to1%, more preferably from 0 to 0.5%, particularly preferably from 0 to0.1%.

SrO is a component that reduces the viscosity at high temperature ofglass to enhance the meltability and formability, and increases thestrain point and Young's modulus. However, when the content thereof istoo large in glass, an ion exchange reaction is liable to be inhibited,and moreover, the density and thermal expansion coefficient increase,and the devitrification of the glass occurs easily. Thus, the content ofSrO is preferably from 0 to 2%, more preferably from 0 to 1.5%, morepreferably from 0 to 1%, more preferably from 0 to 0.5%, more preferablyfrom 0 to 0.1%, particularly preferably from 0 to less than 0.1%.

BaO is a component that reduces the viscosity at high temperature ofglass to enhance the meltability and formability, and increases thestrain point and Young's modulus. However, when the content of BaO istoo large in glass, an ion exchange reaction is liable to be inhibited,and moreover, the density and thermal expansion coefficient increase,and the devitrification of the glass occurs easily. Thus, the content ofBaO is preferably from 0 to 6%, more preferably from 0 to 3%, morepreferably from 0 to 1.5%, more preferably from 0 to 1%, more preferablyfrom 0 to 0.5%, more preferably from 0 to 0.1%, particularly preferablyfrom 0 to less than 0.1%.

When the content of MgO+CaO+SrO+BaO is too large in glass, there is atendency that the density and the thermal expansion coefficientincrease, the glass devitrifies, and the ion exchange performancelowers. Thus, the content of MgO+CaO+SrO+BaO is preferably from 0 to9.9%, more preferably from 0 to 8%, more preferably from 0 to 6%,particularly preferably from 0 to 5%.

When a molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) increases, thedenitrification resistance lowers, the ion exchange performance lowers,and the density and the thermal expansion coefficient increaseexcessively. Thus, the upper limit range of the molar ratio(MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) is preferably 1 or less, more preferably0.9 or less, more preferably 0.8 or less, more preferably 0.75 or less,more preferably 0.70 or less, more preferably 0.65 or less, morepreferably 0.60 or less, particularly preferably 0.55 or less. However,when the molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) reduces excessively,the viscosity at high temperature increases excessively and the ionexchange performance lowers contrarily. Thus, the lower limit range ofthe molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) is preferably 0 or more,more preferably 0.05 or more, more preferably 0.10 or more, particularlypreferably 0.12 or more.

TiO₂ is a component that enhances the ion exchange performance of glassand is a component that reduces the viscosity at high temperature.However, when the content of TiO₂ is too large in glass, the glass isliable to be colored and to denitrify. Thus, the content of TiO₂ ispreferably from 0 to 4.5%, more preferably from 0 to 0.5%, particularlypreferably from 0 to 0.3%.

ZrO₂ is a component that remarkably enhances the ion exchangeperformance of glass, and is a component that increases the viscosity ofglass around the liquidus viscosity and the strain point. However, whenthe content of ZrO₂ is too large in glass, there is a risk that thedenitrification resistance may lower markedly, and there is also a riskthat the density may increase excessively. Thus, the content of ZrO₂ ispreferably from 0 to 5%, more preferably from 0 to 4%, more preferablyfrom 0 to 3%, particularly preferably from 0.001 to 2%.

ZnO is a component that enhances the ion exchange performance of glassand is a component that has a great effect of increasing the compressionstress value, in particular. Further, ZnO is a component that reducesthe viscosity at high temperature of glass without reducing theviscosity at low temperature. However, when the content of ZnO is toolarge in glass, there is a tendency that the glass undergoes phaseseparation, the denitrification resistance lowers, the densityincreases, and the thickness of the compression stress layer decreases.Thus, the content of ZnO is preferably from 0 to 6%, more preferablyfrom 0 to 5%, more preferably from 0 to 3%, particularly preferably from0 to 1%.

P₂O₅ is a component that enhances the ion exchange performance of glassand is a component that increases the thickness of the compressionstress layer, in particular. However, when the content of P₂O₅ is toolarge in glass, the glass undergoes phase separation, and the waterresistance is liable to lower. Thus, the content of P₂O₅ is preferablyfrom 0 to 10%, more preferably from 0 to 3%, more preferably from 0 to1%, particularly preferably from 0 to 0.5%.

As a fining agent, one kind or two or more kinds selected from the groupconsisting of Cl, SO₃, and CeO₂ (preferably the group consisting of Cland SO₃) may be added at from 0 to 3%.

SnO₂ has an effect of enhancing ion exchange performance. Thus, thecontent of SnO₂ is preferably from 0 to 3%, more preferably from 0.01 to3%, more preferably from 0.05 to 3%, more preferably from 0.1 to 3%,particularly preferably from 0.2 to 3%.

The content of SnO₂+SO₃+Cl is preferably from 0.01 to 3%, morepreferably from 0.05 to 3%, more preferably from 0.1 to 3%, particularlypreferably from 0.2 to 3% from the viewpoint of simultaneously achievinga fining effect and an effect of enhancing ion exchange performance. Itshould be noted that the term “SnO₂+SO₃+Cl” refers to the total amountof SnO₂, Cl, and SO₃.

The content of Fe₂O₃ is preferably less than 1,000 ppm (less than 0.1%),more preferably less than 800 ppm, more preferably less than 600 ppm,more preferably less than 400 ppm, particularly preferably less than 300ppm. Further, the molar ratio Fe₂O₃/(Fe₂O₃+SnO₂) is controlled topreferably 0.8 or more, more preferably 0.9 or more, particularlypreferably 0.95 or more, while the content of Fe₂O₃ is controlled in theabove-mentioned range. With this, the transmittance (400 to 770 nm) ofglass having a thickness of 1 mm is likely to improve (by, for example,90% or more).

A rare earth oxide such as Nd₂O₃ or La₂O₃ is a component that enhancesthe Young's modulus. However, the cost of the raw material itself ishigh, and when the rare earth oxide is added in a large amount, thedenitrification resistance is liable to deteriorate. Thus, the contentof the rare earth oxide is preferably 3% or less, more preferably 2% orless, more preferably 1% or less, more preferably 0.5% or less,particularly preferably 0.1% or less.

The tempered glass of the present invention is substantially free ofAs₂O₃, Sb₂O₃, PbO, and F as a glass composition from the standpoint ofenvironmental considerations. In addition, the tempered glass ispreferably substantially free of Bi₂O₃ from the standpoint ofenvironmental considerations. The gist of the phrase “substantially freeof Bi₂O₃” resides in that Bi₂O₃ is not added positively as a glasscomponent, but contamination with Bi₂O₃ as an impurity is allowable.Specifically, the phrase means that the content of Bi₂O₃ is less than0.05%.

When it is desired to achieve both high ion exchange performance and alow crack generation rate, a molar ratio B₂O₃/Al₂O₃ is preferablyregulated within the range of from 0.0 to 0.2, in particular from 0.0 to0.1, and a molar ratio Na₂O/Al₂O₃ is preferably regulated within therange of from 0.8 to 1.2, in particular, from 0.9 to 1.1. Herein, the“crack generation rate” refers to a value measured as described below.First, in a constant temperature and humidity chamber kept at a humidityof 30% and a temperature of 25° C., a Vickers indenter set to apredetermined load is driven into a glass surface (optically polishedsurface) for 15 seconds, and 15 seconds after that, the number of cracksgenerated from the four corners of the indentation is counted (4 perindentation at maximum). The indenter is driven in this manner 20 times,the total number of generated cracks is determined, and then the crackgeneration rate is determined by the following expression: total numberof generated cracks/80×100. In addition, when it is desired to achievehigh levels of both the ion exchange performance and the denitrificationresistance, 18.5 to 23.5% of Al₂O₃, the content of Na₂O is preferablyregulated within the range of from 13.8 to 16.3, and more than 16.0 to25% of Al₂O₃, the content of B₂O₃ is preferably regulated within therange of from 0.01 to 3.95%. It should be noted that the suitablecontent range of each component can be appropriately selected to attaina suitable glass composition range. Of those, particularly suitableglass composition ranges are as follows:

(1) comprising as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, and 5 to 25%of Na₂O, and being substantially free of As₂O₃, Sb₂O₃, PbO, and F;(2) comprising as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, 5 to 25%of Na₂O, and 0 to 2% of SrO, and being substantially free of As₂O₃,Sb₂O₃, PbO, and F;(3) comprising as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, 5 to 25%of Na₂O, 0 to 2% of SrO, 0 to 9.9% of MgO+CaO+SrO+BaO, and 0 to 0.5% ofTiO₂, and being substantially free of As₂O₃, Sb₂O₃, PbO, and F;(4) comprising as a glass composition, in terms of mass %, 50 to 76% ofSiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% ofLi₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 0.5% of TiO₂,and 0 to 4% of ZrO₂, and being substantially free of As₂O₃, Sb₂O₃, PbO,and F;(5) comprising as a glass composition, in terms of mass %, 50 to 76% ofSiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, O to less than1.0% of Li₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 9.9% ofMgO+CaO+SrO+BaO, 0 to 0.5% of TiO₂, 0 to 4% of ZrO₂, and 0 to 1% ofP₂O₅, and being substantially free of As₂O₃, Sb₂O₃, PbO, and F;(6) comprising as a glass composition, in terms of mass %, 50 to 76% ofSiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.0% ofLi₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 9.9% ofMgO+CaO+SrO+BaO, 0 to 0.5% of TiO₂, 0 to 4% of ZrO₂, and to 1% of P₂O₅,having a calculated value in terms of mol %(MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.60, and beingsubstantially free of As₂O₃, Sb₂O₃, PbO, and F;(7) comprising as a glass composition, in terms of mass %, 50 to 76% ofSiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, O to less than1.0% of Li₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 9.9% ofMgO+CaO+SrO+BaO, 0 to 0.5% of TiO₂, 0 to 4% of ZrO₂, 0.2 to 3% of SnO₂,and 0 to 1% of P₂O₅, having a molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃)of from 0 to 0.60, and being substantially free of As₂O₃, Sb₂O₃, PbO,and F; and(8) comprising as a glass composition, in terms of mass %, 50 to 73% ofSiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, O to less than1.0% of Li₂O, more than 7.0 to 25% of Na₂O, 10 to 30% of Li₂O+Na₂O+K₂O,0 to 2% of SrO, 0 to 9.9% of MgO+CaO+SrO+BaO, 0 to 0.5% of TiO₂, 0 to 2%of ZrO₂, 0.2 to 3% of SnO₂, and 0 to 1% of P₂O₅, having a molar ratio(MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.55, and beingsubstantially free of As₂O₃, Sb₂O₃, PbO, and F.

The tempered glass of the present invention preferably has the followingcharacteristics, for example.

The tempered glass of the present invention has a compression stresslayer in a surface thereof. The compression stress value of thecompression stress layer is preferably 300 MPa or more, more preferably400 MPa or more, more preferably 500 MPa or more, more preferably 600MPa or more, particularly preferably 900 MPa or more. As the compressionstress value becomes larger, the mechanical strength of the temperedglass becomes higher. Meanwhile, when an excessively high compressionstress is formed in the surface, there is a risk that a tensile stressinside the tempered glass may increase excessively to increase adimensional change at the time of tempering. Accordingly, thecompression stress value of the compression stress layer is preferably1,200 MPa or less. It shouldbe noted that there is a tendency that thecompression stress value is increased by increasing the content ofAl₂O₃, TiO₂, ZrO₂, MgO, or ZnO in the glass composition or by decreasingthe content of SrO or BaO in the glass composition. Further, there is atendency that the compression stress value is increased by shortening atime necessary for ion exchange or by decreasing the temperature of anion exchange solution.

The thickness of the compression stress layer is preferably 10 μm ormore, more preferably 15 μm or more, more preferably 20 μm or more,particularly preferably 30 μm or more. As the thickness of thecompression stress layer becomes larger, the tempered glass is morehardly cracked even when the tempered glass has a deep flaw, and avariation in the mechanical strength of the tempered glass becomessmaller. Meanwhile, as the thickness of the compression stress layerincreases, it becomes more difficult to cut the tempered glass. Inaddition, there is a risk that a tensile stress inside the temperedglass may increase excessively to increase a dimensional change at thetime of tempering. Accordingly, the thickness of the compression stresslayer is preferably 60 μm or less. It should be noted that there is atendency that the thickness of the compression stress layer is increasedby increasing the content of K₂O or P₂O₅ in the glass composition or bydecreasing the content of SrO or BaO in the glass composition. Further,there is a tendency that the thickness of the compression stress layeris increased by lengthening a time necessary for ion exchange or byincreasing the temperature of an ion exchange solution.

The tempered glass of the present invention has a density of preferably2.6 g/cm³ or less, more preferably 2.55 g/cm³ or less, more preferably2.50 g/cm³ or less, more preferably 2.48 g/cm³ or less, more preferably2.46 g/cm³ or less, particularly preferably 2.45 g/cm³ or less. As thedensity becomes smaller, the weight of the tempered glass can be reducedmore. It should be noted that the density is easily reduced byincreasing the content of SiO₂, B₂O₃, or P₂O₅ in the glass compositionor by decreasing the content of an alkali metal oxide, an alkaline earthmetal oxide, ZnO, ZrO₂, or TiO₂ in the glass composition.

The tempered glass of the present invention has a thermal expansioncoefficient in a temperature range of from 25 to 380° C. of 100×10⁻⁷/°C. or less, preferably 95×10⁻⁷/° C. or less, more preferably 90×10⁻⁷/°C. or less, particularly preferably 85×10⁻⁷/° C. or less. When thethermal expansion coefficient is regulated within the above-mentionedrange, the thermal expansion coefficient can be easily matched with thatof a member such as a metal or an organic adhesive, which makes it easyto prevent the detachment of the member such as the metal or the organicadhesive. It should be noted that an increase in the content of analkali metal oxide or alkaline earth metal oxide in the glasscomposition is likely to increase the thermal expansion coefficient, andconversely, a reduction in the content of the alkali metal oxide oralkaline earth metal oxide is likely to lower the thermal expansioncoefficient.

The tempered glass of the present invention has a temperature at10^(4.0) dPa·s of 1,300° C. or less, preferably 1,280° C. or less, morepreferably 1,250° C. or less, more preferably 1,220° C. or less,particularly preferably 1,200° C. or less. As the temperature at10^(4.0) dPa·s becomes lower, a burden on a forming facility is reducedmore, the forming facility has a longer life, and consequently, themanufacturing cost of the tempered glass is more likely to be reduced.The temperature at 10^(4.0) dPa·s is easily decreased by increasing thecontent of an alkali metal oxide, an alkaline earth metal oxide, ZnO,B₂O₃, or TiO₂ or by reducing the content of SiO₂ or Al₂O₃.

The tempered glass of the present invention has a temperature at10^(2.5) dPa·s of 1,650° C. or less, preferably 1,600° C. or less, morepreferably 1,580° C. or less, particularly preferably 1,550° C. or less.As the temperature at 10^(2.5) dPa·s becomes lower, melting at lowertemperature can be carried out, and hence a burden on glassmanufacturing equipment such as a melting furnace is reduced more, andthe bubble quality of glass is improved more easily. That is, as thetemperature at 10^(2.5) dPa·s becomes lower, the manufacturing cost ofthe tempered glass is more likely to be reduced. Herein, the“temperature at 10^(2.5) dPa·s” can be measured by, for example, aplatinum sphere pull up method. It should be noted that the temperatureat 10^(2.5) dPa·s corresponds to a melting temperature. In addition, anincrease in the content of an alkali metal oxide, alkaline earth metaloxide, ZnO, B₂O₃, or TiO₂ in the glass composition or a reduction in thecontent of SiO₂ or Al₂O₃ is likely to lower the temperature at 10^(2.5)dPa·s.

The tempered glass of the present invention has a liquidus temperatureof 1,200° C. or less, preferably 1,150° C. or less, more preferably1,100° C. or less, more preferably 1,080° C. or less, more preferably1,050° C. or less, more preferably 1,020° C. or less, particularlypreferably 1,000° C. or less. It should be noted that as the liquidustemperature becomes lower, the denitrification resistance andformability are improved more. It should be noted that the liquidustemperature is easily decreased by increasing the content of Na₂O, K₂O,or B₂O₃ in the glass composition or by reducing the content of Al₂O₃,Li₂O, MgO, ZnO, TiO₂, or ZrO₂.

The tempered glass of the present invention has a liquidus viscosity ofpreferably 10^(4.0) dPa·s or more, more preferably 10^(4.4) dPa·s ormore, more preferably 10^(4.8) dPa·s or more, more preferably 10^(5.0)dPa·s or more, more preferably 10^(5.3) dPa·s or more, more preferably10^(5.5) dPa·s or more, more preferably 10^(5.7) dPa·s or more, morepreferably 10^(5.8) dPa·s or more, particularly preferably 10^(6.0)dPa·s or more. It should be noted that as the liquidus viscosity becomeshigher, the denitrification resistance and formability are improvedmore. Further, the liquidus viscosity is easily increased by increasingthe content of Na₂O or K₂O in the glass composition or by reducing thecontent of Al₂O₃, Li₂O, MgO, ZnO, TiO₂, or ZrO₂ in the glasscomposition.

The tempered glass of the present invention has a Young's modulus of 65GPa or more, preferably 69 GPa or more, more preferably 71 GPa or more,more preferably 75 GPa or more, particularly preferably 77 GPa or more.As the Young's modulus increases, the tempered glass is less liable todeflect, and in its use in a touch panel display or the like, the amountof deformation of the tempered glass reduces even when the surface ofthe tempered glass is strongly pressed with a pen or the like. As aresult, it becomes easier to prevent a situation in which the temperedglass is brought into contact with a liquid crystal device locatedbehind the tempered glass to cause a display failure. In addition, theamount of deformation with respect to a stress to be generated at thetime of tempering treatment reduces, and hence a dimensional changebetween before and after tempering treatment is reduced.

A tempered glass sheet of the present invention comprises the temperedglass described above. Thus, technical features (suitablecharacteristics, suitable component ranges, and the like) of thetempered glass sheet of the present invention are the same as thetechnical features of the tempered glass of the present invention.Accordingly, detailed descriptions of the technical features of thetempered glass sheet of the present invention are omitted here.

The tempered glass sheet of the present invention has a fictivetemperature Tf of 500° C. or more, preferably from 520° C. to 700° C.,particularly preferably from 550° C. to 750° C. As the fictivetemperature Tf increases, the structure of the tempered glass can bemore easily relaxed, and hence a dimensional change between before andafter tempering treatment reduces. As a result, the dimensional accuracyof the tempered glass sheet can be increased. It should be noted thatthe fictive temperature Tf can be controlled by adjusting formingconditions in an overflow down-draw method.

The surface of the tempered glass sheet of the present invention has anaverage surface roughness (Ra) of preferably 10 Å or less, morepreferably 8 Å or less, more preferably 6 Å or less, more preferably 4 Åor less, more preferably 3 Å or less, particularly preferably 2 Å orless. As the average surface roughness (Ra) increases, the mechanicalstrength of the tempered glass sheet tends to become lower. Herein, theaverage surface roughness (Ra) refers to a value measured by a method inconformity with SEMI D7-97 “FPD Glass Substrate Surface RoughnessMeasurement Method.”

The tempered glass sheet of the present invention has a length dimensionof 500 mm or more, preferably 700 mm or more, particularly preferably1,000 mm or more and a width dimension of 500 mm or more, preferably 700mm or more, particularly preferably 1,000 mm or more. An increase in thesize of the tempered glass sheet enables the tempered glass sheet to besuitably used as a cover glass for the display portion of the display ofa large-size TV or the like.

The upper limit range of the sheet thickness of the tempered glass sheetof the present invention is 2.0 mm or less, preferably 1.5 mm or less,more preferably 1.3 mm or less, more preferably 1.1 mm or less, morepreferably 1.0 mm or less, more preferably 0.8 mm or less, particularlypreferably 0.7 mm or less. Meanwhile, when the sheet thickness isexcessively small, desired mechanical strength is difficult to obtain.Thus, the sheet thickness is 0.1 mm or more, preferably 0.2 mm or more,more preferably 0.3 mm or more, more preferably 0.4 mm or more,particularly preferably 0.5 mm or more.

A glass to be tempered of the present invention is a glass to besubjected to tempering treatment, comprising as a glass composition, interms of mass %, 50 to 80% of SiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃,0 to 2% of Li₂O, and 5 to 25% of Na₂O, and being substantially free ofAs₂O₃, Sb₂O₃, PbO, and F. Thus, technical features (suitablecharacteristics, suitable component ranges, and the like) of the glassto be tempered of the present invention are the same as the technicalfeatures of the tempered glass of the present invention or the temperedglass sheet of the present invention. Accordingly, detailed descriptionsof the technical features of the glass to be tempered of the presentinvention are omitted here.

The glass to be tempered of the present invention has a dimensionalchange rate S between before and after tempering treatment (immersion ina KNO₃ molten salt at 440° C. for 6 hours) of from −1,000 ppm to +1,000ppm, preferably from −500 ppm to +800 ppm, more preferably from −200 ppmto +600 ppm, particularly preferably from −100 ppm to +500 ppm. Thedimensional change rate S between before and after tempering treatmentcan be made close to 0 to the extent possible by increasing the Young'smodulus, increasing the fictive temperature Tf, reducing the compressionstress value of the compression stress layer, and reducing the thicknessof the compression stress layer.

When the glass to be tempered of the present invention is subjected toion exchange treatment in a KNO₃ molten salt at 430° C., it is preferredthat the compression stress value of a compression stress layer in asurface thereof be 300 MPa or more and the thickness of the compressionstress layer be 10 μm or more, it is more preferred that the compressionstress of the surface thereof be 600 MPa or more and the thickness ofthe compression stress layer be 30 μm or more, and it is particularlypreferred that the compression stress of the surface thereof be 700 MPaor more and the thickness of the compression stress layer be 30 μm ormore.

When the ion exchange treatment is performed, the temperature of theKNO₃ molten salt is preferably from 400 to 550° C., and the ion exchangetime is preferably from 1 to 10 hours, particularly preferably from 2 to8 hours. With this, the compression stress layer can be properly formedeasily. It should be noted that the glass to be tempered of the presentinvention has the above-mentioned glass composition, and hence thecompression stress value and thickness of the compression stress layercan be increased without using a mixture of a KNO₃ molten salt and aNaNO₃ molten salt or the like.

The glass to be tempered of the present invention has a fictivetemperature Tf of 500° C. or more, preferably from 520° C. to 700° C.,particularly preferably from 550° C. to 750° C. As the fictivetemperature Tf increases, the structure of the tempered glass can bemore easily relaxed, and hence a dimensional change between before andafter tempering treatment reduces. As a result, the dimensional accuracyof the tempered glass sheet can be increased. It should be noted thatthe fictive temperature Tf can be controlled by adjusting formingconditions in an overflow down-draw method.

In order to increase the fictive temperature Tf, a cooling rate ispreferably increased and a sheet drawing rate is preferably increased.However, when the sheet drawing rate is increased, there is a risk thatthe glass may reach a cutting step before being sufficiently cooled. Inorder to prevent such situation, an overflow down-draw method is adoptedas a forming method and the glass is cut at a position spaced apartdownwardly by 1,000 mm or more, preferably 2,000 mm or more,particularly preferably 3,000 mm or more from the lower end of a formingtrough used in the overflow down-draw method.

A crack generation rate before tempering treatment at a load of 1,000 gfis preferably 99% or less, more preferably 90% or less, more preferably80% or less, more preferably 70% or less, more preferably 60% or less,more preferably 65% or less, particularly preferably 50% or less. As thecrack generation rate reduces, a surface flaw is less liable to becreated on the tempered glass, and hence the mechanical strength of thetempered glass is less liable to lower. In addition, the mechanicalstrength is less liable to vary. In addition, when the crack generationrate is low, a lateral crack is hardly generated at the time ofpost-tempering cutting such as post-tempering scribe cutting, and hencethe post-tempering cutting can be easily performed appropriately. As aresult, the manufacturing cost of a device can be easily reduced.

It is preferred that the glass to be tempered of the present inventionbe not devitrified at a contact interface when the glass to be temperedhas a viscosity of 10^(4.5) dPa·s and is brought into contact for 48hours with a material for a forming trough (such as dense zircon oralumina, in particular, alumina) to be used in an overflow down-drawmethod.

The glass to be tempered, tempered glass, and tempered glass sheet ofthe present invention can be produced as described below.

First, glass raw materials, which have been blended so as to have theabove-mentioned glass composition, are loaded in a continuous meltingfurnace, are melted by heating at from 1,500 to 1,600° C., and arefined. After that, the resultant is fed to a forming apparatus, isformed into a sheet shape or the like, and is annealed. Thus, a glasssheet or the like can be produced.

An overflow down-draw method is preferably adopted as a method offorming the glass sheet. The overflow down-draw method is a method bywhich a high-quality glass sheet can be produced in a large amount, andby which even a large-size glass sheet can be easily produced. Inaddition, the fictive temperature Tf of the glass sheet can be easilyincreased. Further, in the overflow down-draw method, alumina or densezircon is used as a forming trough. The glass to be tempered of thepresent invention has satisfactory compatibility with alumina and densezircon, in particular, alumina (hardly reacts with the forming trough togenerate bubbles, glass stones, or the like).

Various forming methods other than the overflow down-draw method mayalso be adopted. For example, forming methods such as a float method, adown draw method (such as a slot down method or a re-draw method), aroll out method, and a press method may be adopted.

Next, the resultant glass to be tempered is subjected to temperingtreatment, thereby being able to produce a tempered glass. The resultanttempered glass may be cut into pieces having predetermined sizes beforethe tempering treatment or after the tempering treatment.

The tempering treatment is preferably ion exchange treatment. Conditionsfor the ion exchange treatment are not particularly limited, and optimumconditions may be selected in view of, for example, the viscosityproperties, applications, thickness, inner tensile stress, anddimensional change of glass. The ion exchange treatment can beperformed, for example, by immersing glass in a KNO₃ molten salt at 400to 550° C. for 1 to 8 hours. Particularly when the ion exchange of Kions in the KNO₃ molten salt with Na components in the glass isperformed, it is possible to form efficiently a compression stress layerin a surface of the glass.

Example 1

The present invention is hereinafter described based on Examples. Itshould be noted that Examples are merely illustrative. The presentinvention is by no means limited to Examples.

Tables 1 to 34 show Examples of the present invention (sample Nos. 1 to204).

TABLE 1 Example No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 Glass SiO₂ 60.0 59.859.9 59.8 59.9 59.9 composition Al₂O₃ 17.8 17.9 17.9 17.9 17.9 17.9(mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 12.2 13.3 14.2 15.2 12.3 13.3K₂O 5.0 4.0 3.0 2.1 5.0 4.0 MgO 1.0 1.0 1.0 1.0 2.9 2.9 CaO 3.0 3.0 3.03.0 1.0 1.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.43 0.43 0.43 0.430.50 0.49 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density (g/cm³) 2.472.48 2.48 2.48 2.46 2.46 α (×10⁻⁷/° C.) 95 95 95 94 93 95 E Unmea-Unmea- Unmea- Unmea- 72 72 sured sured sured sured Ps (° C.) 557 555 552550 571 568 Ta (° C.) 603 600 596 594 620 616 Ts (° C.) 830 823 815 809861 853 10⁴ dPa · s (° C.) 1,218 1,209 1,197 1,185 1,250 1,237 10³ dPa ·s (° C.) 1,427 1,416 1,403 1,389 1,452 1,437 10^(2.5) dPa · s (° C.)1,555 1,547 1,533 1,518 1,578 1,564 TL (° C.) 1,016 992 977 974 9861,002 log₁₀η_(TL) (dPa · s) 5.4 5.6 5.6 5.6 6.1 5.8 CS (MPa) 823 831 830831 897 930 DOL (μm) 49 46 42 39 57 52 Fictive temperature Unmea- Unmea-Unmea- Unmea- Unmea- Unmea- (° C.) sured sured sured sured sured suredDimensional change Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- rate (ppm)sured sured sured sured sured sured Crack generation rate Unmea- Unmea-Unmea- Unmea- Unmea- Unmea- (%) sured sured sured sured sured suredCompatibility with Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- aluminasured sured sured sured sured sured

TABLE 2 Example No. 7 No. 8 No. 9 No. 10 No. 11 No. 12 Glass SiO₂ 59.859.7 57.8 57.8 57.8 57.7 composition Al₂O₃ 18.0 18.0 19.9 19.9 19.9 19.9(mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 14.3 15.3 12.3 13.3 14.3 15.3K₂O 3.0 2.1 5.0 4.0 3.0 2.1 MgO 2.9 2.9 1.0 1.0 1.0 1.0 CaO 1.0 1.0 3.03.0 3.0 3.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.49 0.50 0.39 0.390.39 0.39 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density (g/cm³) 2.472.47 2.48 2.48 2.48 2.49 α (×10⁻⁷/° C.) 94 94 95 95 95 95 E 72 72 Unmea-Unmea- Unmea- 73 sured sured sured Ps (° C.) 565 563 573 570 567 566 Ta(° C.) 613 610 621 616 612 611 Ts (° C.) 844 838 853 844 836 831 10⁴ dPa· s (° C.) 1,227 1,214 1,245 1,232 1,218 1,205 10³ dPa · s (° C.) 1,4261,412 1,448 1,437 1,421 1,406 10^(2.5) dPa · s (° C.) 1,551 1,538 1,5741,564 1,548 1,532 TL (° C.) 982 1,046 1,074 1,030 1,011 1,006log₁₀η_(TL) (dPa · s) 5.9 5.2 5.2 5.5 5.5 5.5 CS (MPa) 935 937 978 1,0171,024 1,019 DOL (μm) 48 46 50 46 43 40 Fictive temperature Unmea- Unmea-Unmea- Unmea- Unmea- Unmea- (° C.) sured sured sured sured sured suredDimensional change Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- rate (ppm)sured sured sured sured sured sured Crack generation rate Unmea- Unmea-Unmea- Unmea- Unmea- Unmea- (%) sured sured sured sured sured suredCompatibility with Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- aluminasured sured sured sured sured sured

TABLE 3 Example No. 13 No. 14 No. 15 No. 16 No. 17 No. 18 Glass SiO₂57.9 57.9 57.9 57.7 59.5 58.4 composition Al₂O₃ 19.9 19.9 19.9 20.0 19.320.4 (mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 12.3 13.3 14.3 15.3 15.115.1 K₂O 5.0 4.0 3.0 2.1 2.1 2.1 MgO 2.9 2.9 2.9 2.9 1.0 1.0 CaO 1.0 1.01.0 1.0 2.0 2.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.45 0.44 0.450.45 0.30 0.29 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density (g/cm³)2.47 2.47 2.47 2.47 2.47 2.47 α (×10⁻⁷/° C.) 95 94 94 94 94 93 E 73Unmea- Unmea- 72 72 72 sured sured Ps (° C.) 590 585 583 579 566 574 Ta(° C.) 640 635 631 627 612 621 Ts (° C.) 884 875 867 861 841 854 10⁴ dPa· s (° C.) 1,272 1,255 1,243 1,232 1,233 1,243 10³ dPa · s (° C.) 1,4681,450 1,437 1,426 1,441 1,450 10^(2.5) dPa · s (° C.) 1,588 1,570 1,5581,546 1,571 1,578 TL (° C.) 1,080 1,068 1,049 1,036 974 991 log₁₀η_(TL)(dPa · s) 5.4 5.4 5.5 5.5 5.9 5.9 CS (MPa) 1,070 1,098 1,132 1,150 9641,037 DOL (μm) 56 53 48 45 44 45 Fictive temperature Unmea- Unmea-Unmea- Unmea- Unmea- Unmea- (° C.) sured sured sured sured sured suredDimensional change Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- rate (ppm)sured sured sured sured sured sured Crack generation rate Unmea- Unmea-54 Unmea- 43 Unmea- (%) sured sured sured sured Compatibility withUnmea- Unmea- Unmea- Unmea- Unmea- Unmea- alumina sured sured suredsured sured sured

TABLE 4 Example No. 19 No. 20 No. 21 No. 22 No. 23 No. 24 Glass SiO₂57.9 58.0 59.0 57.8 57.9 57.8 composition Al₂O₃ 19.9 19.8 19.9 20.9 19.919.9 (mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 16.1 15.1 15.1 15.2 16.215.2 K₂O 2.1 3.1 2.1 2.1 2.1 3.1 MgO 1.0 1.0 1.9 2.0 1.9 2.0 CaO 2.0 2.01.0 1.0 1.0 1.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.30 0.30 0.330.31 0.33 0.33 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density (g/cm³)2.48 2.48 2.46 2.47 2.47 2.47 α (×10⁻⁷/° C.) 97 97 94 94 97 98 E 72 7272 72 72 72 Ps (° C.) 559 561 578 587 566 568 Ta (° C.) 604 607 627 637613 616 Ts (° C.) 826 833 865 876 842 852 10⁴ dPa · s (° C.) 1,207 1,2191,253 1,264 1,225 1,236 10³ dPa · s (° C.) 1,411 1,425 1,455 1,463 1,4251,437 10^(2.5) dPa · s (° C.) 1,539 1,554 1,581 1,587 1,551 1,563 TL (°C.) 1,008 1,022 1,037 1,099 1,026 1,053 log₁₀η_(TL) (dPa · s) 5.5 5.45.6 5.2 5.5 5.3 CS (MPa) 935 957 1,085 1,140 1,018 1,001 DOL (μm) 45 4849 49 49 53 Fictive temperature Unmea- Unmea- Unmea- Unmea- Unmea-Unmea- (° C.) sured sured sured sured sured sured Dimensional changeUnmea- Unmea- Unmea- Unmea- Unmea- Unmea- rate (ppm) sured sured suredsured sured sured Crack generation rate Unmea- Unmea- 61 Unmea- Unmea-Unmea- (%) sured sured sured sured sured Compatibility with Unmea-Unmea- Unmea- Unmea- Unmea- Unmea- alumina sured sured sured sured suredsured

TABLE 5 Example No. 25 No. 26 No. 27 No. 28 No. 29 No. 30 Glass SiO₂59.4 59.4 59.4 59.4 59.4 59.7 composition Al₂O₃ 18.7 18.7 18.7 18.7 19.719.5 (mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 12.0 15.0 12.0 15.0 12.014.8 K₂O 5.0 2.0 5.0 2.0 4.0 1.1 MgO 2.9 2.9 3.9 3.9 2.9 2.9 CaO 1.0 1.00.0 0.0 1.0 1.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.47 0.47 0.510.51 0.45 0.45 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density (g/cm³)2.46 2.47 2.46 2.46 2.46 2.46 α (×10⁻⁷/° C.) 93 93 93 89 89 80 E 73 7272 72 73 72 Ps (° C.) 580 571 595 586 598 590 Ta (° C.) 630 619 648 650650 640 Ts (° C.) 879 853 896 902 902 880 10⁴ dPa · s (° C.) 1,270 1,2301,277 1,242 1,286 1,256 10³ dPa · s (° C.) 1,471 1,428 1,474 1,435 1,4821,452 10^(2.5) dPa · s (° C.) 1,600 1,553 1,596 1,558 1,600 1,573 TL (°C.) 1,052 1,004 Unmea- 1,115 1,126 1,105 sured log₁₀η_(TL) (dPa · s) 5.65.8 Unmea- 5.0 5.1 5.1 sured CS (MPa) 948 1,005 964 1,040 1,011 1,095DOL (μm) 58 46 62 49 54 42 Fictive temperature Unmea- Unmea- Unmea-Unmea- Unmea- Unmea- (° C.) sured sured sured sured sured suredDimensional change Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- rate S(ppm) sured sured sured sured sured sured Crack generation rate 41 35Unmea- Unmea- Unmea- Unmea- (%) sured sured sured sured Compatibilitywith Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- alumina sured sured suredsured sured sured

TABLE 6 Example No. 31 No. 32 No. 33 No. 34 No. 35 No. 36 Glass SiO₂58.2 59.1 58.5 59.5 58.0 58.0 composition Al₂O₃ 19.3 19.3 19.5 18.5 19.019.0 (mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 11.8 14.7 15.0 15.0 15.015.0 K₂O 4.9 1.1 2.0 2.0 2.0 2.0 MgO 3.8 3.8 3.0 3.0 4.0 3.0 CaO 1.0 1.01.0 1.0 1.0 1.0 ZnO 0.0 0.0 0.0 0.0 0.0 1.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5Molar ratio 0.57 0.57 0.46 0.49 0.60 0.48 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.47 2.47 2.47 2.47 2.48 2.49 α (×10⁻⁷/°C.) 91 88 94 96 96 95 E 73 73 72 72 73 73 Ps (° C.) 593 592 564 568 575572 Ta (° C.) 643 641 623 616 622 619 Ts (° C.) 886 874 856 847 848 84710⁴ dPa · s (° C.) 1,264 1,241 1,225 1,220 1,204 1,213 10³ dPa · s (°C.) 1,456 1,432 1,420 1,418 1,392 1,405 10^(2.5) dPa · s (° C.) 1,5751,551 1,542 1,540 1,513 1,527 TL (° C.) Unmea- 1,156 1,053 1,004 1,0681,071 sured log₁₀η_(TL) (dPa · s) Unmea- 4.6 5.3 5.7 5.0 5.0 sured CS(MPa) 997 1,147 1,046 989 1,074 1,062 DOL (μm) 53 37 45 45 40 42 Fictivetemperature Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- (° C.) sured suredsured sured sured sured Dimensional change Unmea- Unmea- Unmea- Unmea-Unmea- Unmea- rate S (ppm) sured sured sured sured sured sured Crackgeneration rate Unmea- Unmea- Unmea- Unmea- Unmea- Unmea- (%) suredsured sured sured sured sured Compatibility with Unmea- Unmea- Unmea-Unmea- Unmea- Unmea- alumina sured sured sured sured sured sured

TABLE 7 Example No. 37 No. 38 No. 39 No. 40 No. 41 No. 42 Glass SiO₂64.9 57.3 60.8 60.8 61.8 61.5 composition Al₂O₃ 16.5 13.0 16.3 18.0 17.018.0 (mass %) B₂O₃ 0.0 2.0 0.6 0.5 0.5 0.0 Na₂O 14.7 14.5 14.1 15.1 15.115.0 K₂O 0.0 4.9 3.6 2.1 2.1 2.0 MgO 3.4 2.0 3.6 3.0 3.0 3.0 CaO 0.1 2.00.5 0.0 0.0 0.0 ZrO₂ 0.0 4.0 0.0 0.0 0.0 0.0 SnO₂ 0.4 0.3 0.5 0.5 0.50.5 Molar ratio 0.53 0.55 0.58 0.40 0.42 0.42 (MgO + CaO + SrO +BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.44 2.54 2.46 2.45 2.45 2.45 α(×10⁻⁷/° C.) 83 100 92 94 93 93 E 70 Unmeasured Unmeasured 71 71 71 Ps(° C.) 597 523 557 573 565 581 Ta (° C.) 648 563 605 622 614 632 Ts (°C.) 893 762 846 862 850 875 10⁴ dPa · s (° C.) 1,273 1,100 1,230 1,2461,238 1,258 10³ dPa · s (° C.) 1,476 1,280 1,430 1,449 1,441 1,46010^(2.5) dPa · s (° C.) 1,610 1,396 1,560 1,577 1,570 1,591 TL (° C.)1,045 855 925 1,044 1,035 967 log₁₀η_(TL) (dPa · s) 5.8 6.1 6.6 5.5 5.56.4 CS (MPa) 991 844 895 910 847 986 DOL (μm) 44 44 46 54 54 48 Fictivetemperature Unmeasured Unmeasured 651 Unmeasured Unmeasured Unmeasured(° C.) Dimensional change Unmeasured Unmeasured 525 UnmeasuredUnmeasured Unmeasured rate S (ppm) Crack generation rate UnmeasuredUnmeasured Unmeasured 46 Unmeasured Unmeasured (%) Compatibility with ∘Unmeasured ∘ Unmeasured Unmeasured Unmeasured alumina

TABLE 8 Example No. 43 No. 44 No. 45 No. 46 No. 47 No. 48 Glass SiO₂62.0 61.0 61.5 61.5 62.0 62.0 composition Al₂O₃ 18.0 18.0 18.0 18.0 18.018.0 (mass %) B₂O₃ 0.5 0.5 0.5 0.5 0.5 0.5 Na₂O 15.0 16.0 14.5 15.0 14.014.5 K₂O 1.0 1.0 2.0 2.0 3.0 2.5 MgO 3.0 3.0 3.0 2.5 2.0 2.0 SnO₂ 0.50.5 0.5 0.5 0.5 0.5 Molar ratio 0.41 0.41 0.41 0.34 0.27 0.27 (MgO +CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.45 2.46 2.45 2.45 2.442.44 α (×10⁻⁷/° C.) 89 92 92 92 93 92 E 71 71 71 71 71 71 Ps (° C.) 583571 579 569 567 566 Ta (° C.) 634 620 629 618 617 616 Ts (° C.) 877 855875 862 867 862 10⁴ dPa · s (° C.) 1,262 1,234 1,261 1,249 1,273 1,27110³ dPa · s (° C.) 1,464 1,435 1,463 1,455 1,486 1,483 10^(2.5) dPa · s(° C.) 1,589 1,561 1,589 1,582 1,616 1,614 TL (° C.) 1,009 1,008 1,012984 973 997 log₁₀η_(TL) (dPa · s) 6.0 5.7 5.9 6.1 6.3 6.0 CS (MPa) 986911 961 Unmeasured Unmeasured Unmeasured DOL (μm) 48 49 48 UnmeasuredUnmeasured Unmeasured Fictive temperature Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured (° C.) Dimensional changeUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured rate S(ppm) Crack generation rate 60 Unmeasured 25 Unmeasured UnmeasuredUnmeasured (%) Compatibility with Unmeasured Unmeasured ∘ UnmeasuredUnmeasured Unmeasured alumina

TABLE 9 Example No. 49 No. 50 No. 51 No. 52 No. 53 No. 54 Glass SiO₂63.0 61.0 61.0 61.0 59.0 62.0 composition Al₂O₃ 19.0 19.0 20.0 21.0 21.019.0 (mass %) B₂O₃ 1.0 1.0 1.0 1.0 1.0 1.0 Na₂O 14.5 14.5 14.5 14.5 14.515.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 4.0 3.0 2.0 4.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.25 0.49 0.350.23 0.45 0.25 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.432.45 2.44 2.44 2.46 2.44 α (×10⁻⁷) 82 82 82 82 82 86 E UnmeasuredUnmeasured Unmeasured Unmeasured 73 70 Ps (° C.) 600 602 610 619 616 586Ta (° C.) 653 653 663 675 667 636 Ts (° C.) 911.5 894 913.5 938 908884.5 10⁴ dPa · s (° C.) 1,312 1,259 1,297 1,335 1,276 1,286 10³ dPa · s(° C.) 1,517 1,451 1,494 1,534 1,464 1,494 10^(2.5) dPa · s (° C.) 1,6491,570 1,615 1,656 1,581 1,622 TL (° C.) 993 1,184 1,146 1,076 Unmeasured962 log₁₀η_(TL) (dPa · s) 6.6 4.5 5.1 6.0 Unmeasured 6.6 CS (MPa) 1,1331,224 1,251 1,276 1,315 1,073 DOL (μm) 38 30 33 36 28 38 Fictivetemperature Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured (° C.) Dimensional change Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured rate (ppm) Crack generation rateUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured (%)Compatibility with Unmeasured Unmeasured Unmeasured x UnmeasuredUnmeasured alumina

TABLE 10 Example No. 55 No. 56 No. 57 No. 58 No. 59 No. 60 Glass SiO₂60.0 60.0 60.0 58.0 59.0 61.0 composition Al₂O₃ 19.0 20.0 21.0 21.0 19.019.0 (mass %) B₂O₃ 1.0 1.0 1.0 1.0 1.0 1.0 Na₂O 15.5 15.5 15.5 15.5 16.516.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 4.0 3.0 2.0 4.0 4.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.49 0.35 0.230.45 0.49 0.25 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.462.45 2.44 2.46 2.46 2.45 α (×10⁻⁷) 86 86 86 86 89 88 E 71 71 70 72 71 70Ps (° C.) 592 598 604 606 580 573 Ta (° C.) 641 649 657 656 628 621 Ts(° C.) 875 891.5 910 889 853 856.5 10⁴ dPa · s (° C.) 1,241 1,272 1,3071,252 1,216 1,254 10³ dPa · s (° C.) 1,433 1,468 1,507 1,439 1,405 1,46110^(2.5) dPa · s (° C.) 1,554 1,589 1,630 1,556 1,525 1,589 TL (° C.)1,139 1,091 1,029 1,189 1,075 932 log₁₀η_(TL) (dPa · s) 4.7 5.3 6.2 4.45.0 6.6 CS (MPa) 1,198 1,216 1,226 1,306 1,135 971 DOL (μm) 30 33 37 2930 37 Fictive temperature Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (° C.) Dimensional change Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured rate (ppm) Crack generationrate Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured(%) Compatibility with Unmeasured Unmeasured x Unmeasured UnmeasuredUnmeasured alumina

TABLE 11 Example No. 61 No. 62 No. 63 No. 64 No. 65 No. 66 Glass SiO₂59.0 57.0 59.0 57.0 60.0 62.0 composition Al₂O₃ 20.0 21.0 21.0 23.0 19.019.0 (mass %) B₂O₃ 1.0 1.0 1.0 1.0 0.0 0.0 Na₂O 16.5 16.5 16.5 16.5 16.516.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 3.0 4.0 2.0 2.0 4.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.35 0.45 0.230.21 0.53 0.27 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.462.47 2.45 2.46 2.46 2.45 α (×10⁻⁷) 89 87 89 89 89 89 E 70 72 70Unmeasured 71 70 Ps (° C.) 586 594 590 606 601 591 Ta (° C.) 636 643 640659 651 642 Ts (° C.) 869.5 871 883.5 907 880.5 883.5 10⁴ dPa · s (° C.)1,247 1,229 1,275 1,282 1,238 1,275 10³ dPa · s (° C.) 1,442 1,414 1,4751,473 1,430 1,481 10^(2.5) dPa · s (° C.) 1,563 1,530 1,597 1,591 1,5501,608 TL (° C.) 1,018 1,151 1,004 1,102 1,102 970 log₁₀η_(TL) (dPa · s)5.8 4.5 6.1 5.4 5.0 6.5 CS (MPa) 1,153 1,277 1,152 1,304 1,190 984 DOL(μm) 34 30 38 38 34 42 Fictive temperature Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured (° C.) Dimensional changeUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured rate(ppm) Crack generation rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (%) Compatibility with Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured alumina

TABLE 12 Example No. 67 No. 68 No. 69 No. 70 No. 71 No. 72 Glass SiO₂60.0 58.0 60.0 58.0 58.0 59.0 composition Al₂O₃ 20.0 21.0 21.0 23.0 23.023.0 (mass %) B₂O₃ 0.0 0.0 0.0 0.0 1.0 1.0 Na₂O 16.5 16.5 16.5 16.5 15.514.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 3.0 4.0 2.0 2.0 2.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.38 0.48 0.240.22 0.21 0.21 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.462.47 2.45 2.46 2.45 2.44 α (×10⁻⁷) 90 89 89 90 86 82 E 71 72 70 71 71 71Ps (° C.) 608 617 615 636 618 631 Ta (° C.) 659 667 667 690 673 688 Ts(° C.) 896.5 897.5 913.5 938.5 930.5 954 10⁴ dPa · s (° C.) 1,269 1,2531,301 1,318 1,318 1,343 10³ dPa · s (° C.) 1,465 1,440 1,501 1,510 1,5111,533 10^(2.5) d Pa · s (° C.) 1,586 1,557 1,624 1,630 1,633 1,653 TL (°C.) 1,040 1,174 1,063 Unmeasured 1,081 1,165 log₁₀η_(TL) (dPa · s) 5.84.6 5.8 Unmeasured 5.8 5.3 CS (MPa) 1,178 1,294 1,153 1,310 1,327 1,321DOL (μm) 38 33 43 44 38 39 Fictive temperature Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured (° C.) Dimensional changeUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured rate(ppm) Crack generation rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (%) Compatibility with Unmeasured UnmeasuredUnmeasured Unmeasured x Unmeasured alumina

TABLE 13 Example No. 73 No. 74 No. 75 No. 76 No. 77 No. 78 Glass SiO₂61.0 61.0 61.0 61.0 61.0 59.0 composition Al₂O₃ 19.0 19.0 19.0 19.0 21.021.0 (mass %) B₂O₃ 2.5 2.5 2.5 2.5 0.0 3.0 Na₂O 13.0 12.5 14.0 13.5 15.515.5 K₂O 2.0 2.5 1.5 2.0 0.0 0.0 MgO 2.0 2.0 1.5 1.5 2.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.22 0.22 0.170.17 0.24 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.432.43 2.43 2.43 2.44 2.44 α (×10⁻⁷) 86 86 86 87 87 86 E 70 70 70 70 70 69Ps (° C.) 573 572 571 568 626 574 Ta (° C.) 624 623 621 617 681 623 Ts(° C.) 881.5 882 870 867.5 939 866 10⁴ dPa · s (° C.) 1,308 1,299 1,3021,285 1,331 1,279 10³ dPa · s (° C.) 1,516 1,508 1,516 1,500 1,529 1,47910^(2.5) dPa · s (° C.) 1,643 1,635 1,646 1,631 1,652 1,603 TL (° C.)<990 <990 1,069 1,004 1,046 973 log₁₀η_(TL) (dPa · s) >6.4 >6.4 5.5 6.06.3 6.3 CS (MPa) 992 982 971 956 1,185 1,133 DOL (μm) 40 43 39 40 43 32Fictive temperature Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (° C.) Dimensional change Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured rate (ppm) Crack generationrate Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured(%) Compatibility with x Unmeasured ∘ ∘ Unmeasured Unmeasured alumina

TABLE 14 Example No. 79 No. 80 No. 81 No. 82 No. 83 No. 84 Glass SiO₂58.0 57.0 59.0 58.0 57.0 56.0 composition Al₂O₃ 21.0 21.0 21.0 21.0 21.021.0 (mass %) B₂O₃ 2.0 4.0 0.0 1.0 2.0 3.0 Na₂O 15.5 15.5 15.5 15.5 15.515.5 K₂O 0.0 0.0 2.0 2.0 2.0 2.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.21 0.19 0.240.23 0.21 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.442.44 2.46 2.46 2.45 2.45 α (×10⁻⁷) 86 86 96 95 95 94 E UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) 585 564599 578 569 554 Ta (° C.) 636 612 651 628 618 600 Ts (° C.) 885.5 850901.5 873.5 861 830 10⁴ dPa · s (° C.) 1,278 1,240 1,293 1,268 1,2571,225 10³ dPa · s (° C.) 1,474 1,438 1,494 1,470 1,459 1,426 10^(2.5)dPa · s (° C.) 1,595 1,562 1,616 1,593 1,584 1,552 TL (° C.) 989 <1,0301,054 1,008 996 977 log₁₀η_(TL) (dPa · s) 6.3 >5.5 5.8 6.0 6.0 5.9 CS(MPa) 1,140 1,095 1,078 1,061 1,054 1,030 DOL (μm) 36 31 52 47 43 39Fictive temperature Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (° C.) Dimensional change Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured rate (ppm) Crack generationrate Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured(%) Compatibility with Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured alumina

TABLE 15 Example No. 85 No. 86 No. 87 No. 88 No. 89 No. 90 Glass SiO₂65.1 64.0 62.9 61.8 60.7 63.5 composition Al₂O₃ 19.4 19.4 19.4 19.4 19.421.0 (mass %) B₂O₃ 0.0 1.1 2.2 3.3 4.4 0.0 Na₂O 13.6 13.6 13.6 13.6 13.613.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.4 1.4 1.4 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.18 0.17 0.160.15 0.14 0.17 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.42Unmeasured 2.41 Unmeasured 2.41 Unmeasured α (×10⁻⁷) 79 Unmeasured 79Unmeasured 78 Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) 641 Unmeasured 592 Unmeasured 572Unmeasured Ta (° C.) 700 Unmeasured 646 Unmeasured 624 Unmeasured Ts (°C.) 979.5 Unmeasured 917.5 Unmeasured 884.5 Unmeasured 10⁴ dPa · s (°C.) 1,396 Unmeasured 1,343 Unmeasured 1,300 Unmeasured 10³ dPa · s (°C.) 1,601 Unmeasured 1,553 Unmeasured 1,510 Unmeasured 10^(2.5) dPa · s(° C.) 1,724 Unmeasured 1,683 Unmeasured 1,641 Unmeasured TL (° C.)1,034 Unmeasured <990 Unmeasured 1,004 Unmeasured log₁₀η_(TL) (dPa · s)6.9 Unmeasured >6.7 Unmeasured 6.2 Unmeasured CS (MPa) 1,095 Unmeasured1,047 Unmeasured 1,017 Unmeasured DOL (μm) 46 Unmeasured 37 Unmeasured32 Unmeasured Fictive temperature (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Dimensional change rateUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm)Crack generation rate (%) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Compatibility with ∘ Unmeasured ∘ Unmeasured ∘Unmeasured alumina

TABLE 16 Example No. 91 No. 92 No. 93 No. 94 No. 95 No. 96 Glass SiO₂62.5 61.5 60.5 62.4 61.4 60.4 composition Al₂O₃ 21.0 21.0 21.0 22.3 22.322.3 (mass %) B₂O₃ 1.0 2.0 3.0 0.0 1.0 2.0 Na₂O 13.6 13.6 13.6 13.5 13.513.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.3 1.3 1.3 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.16 0.15 0.140.15 0.14 0.13 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³) 2.42Unmeasured Unmeasured 2.43 Unmeasured 2.42 α (×10⁻⁷) 79 UnmeasuredUnmeasured 79 Unmeasured 79 E Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Ps (° C.) 627 Unmeasured Unmeasured 677643 623 Ta (° C.) 689 Unmeasured Unmeasured 739 704 682 Ts (° C.) 970Unmeasured Unmeasured 1,029 993 966 10⁴ dPa · s (° C.) 1,386 UnmeasuredUnmeasured 1,426 1,394 1,375 10³ dPa · s (° C.) 1,586 UnmeasuredUnmeasured 1,618 1,586 1,570 10^(2.5) dPa · s (° C.) 1,710 UnmeasuredUnmeasured 1,738 1,708 1,693 TL (° C.) 1,133 Unmeasured Unmeasured 1,2301,214 1,199 log₁₀η_(TL) (dPa · s) 5.8 Unmeasured Unmeasured 5.4 5.3 5.2CS (MPa) 1,181 Unmeasured Unmeasured 1,231 1,170 1,220 DOL (μm) 42Unmeasured Unmeasured 48 42 40 Fictive temperature (° C.) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Dimensionalchange rate Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured (ppm) Crack generation rate (%) Unmeasured UnmeasuredUnmeasured 53 Unmeasured 44 Compatibility with ∘ Unmeasured Unmeasured ∘∘ ∘ alumina

TABLE 17 Example No. 97 No. 98 No. 99 No. 100 No. 101 No. 102 Glass SiO₂61.1 60.1 59.8 64.5 63.4 62.3 composition Al₂O₃ 23.6 23.6 25.0 19.4 19.419.4 (mass %) B₂O₃ 0.0 1.0 0.0 0.0 1.1 2.2 Na₂O 13.5 13.5 13.4 13.6 13.613.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.3 1.3 1.3 2.0 2.0 2.0 CaO 0.0 0.00.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.14 0.13 0.130.26 0.24 0.22 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density (g/cm³)Unmeasured Unmeasured 2.44 2.42 Unmeasured 2.42 α (×10⁻⁷) UnmeasuredUnmeasured 76 78 Unmeasured 78 E Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Ps (° C.) 688 655 698 640 Unmeasured589 Ta (° C.) 750 716 760 698 Unmeasured 643 Ts (° C.) 1,040 1,003 1,040971 Unmeasured 909 10⁴ dPa · s (° C.) 1,425 1,401 1,419 1,380 Unmeasured1,326 10³ dPa · s (° C.) 1,610 1,589 1,601 1,585 Unmeasured 1,53210^(2.5) dPa · s (° C.) 1,729 1,706 1,717 1,719 Unmeasured 1,660 TL (°C.) 1,260 1,237 Unmeasured 1,091 Unmeasured 1,058 log₁₀η_(TL) (dPa · s)5.2 5.2 Unmeasured 6.2 Unmeasured 5.9 CS (MPa) 1,182 1,194 1,263 1,140Unmeasured 1,101 DOL (μm) 46 41 42 42 Unmeasured 33 Fictive temperature(° C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) UnmeasuredUnmeasured 22 48 Unmeasured 47 Compatibility with ∘ ∘ ∘ x Unmeasured ∘alumina

TABLE 18 Example No. 103 No. 104 No. 105 No. 106 No. 107 No. 108 GlassSiO₂ 61.2 60.1 62.9 61.9 60.9 59.9 composition Al₂O₃ 19.4 19.4 21.0 21.021.0 21.0 (mass %) B₂O₃ 3.3 4.4 0.0 1.0 2.0 3.0 Na₂O 13.6 13.6 13.6 13.613.6 13.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.210.20 0.24 0.23 0.21 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured 2.41 Unmeasured 2.43 Unmeasured Unmeasured α (×10⁻⁷)Unmeasured 79 Unmeasured 79 Unmeasured Unmeasured E UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Ps (° C.)Unmeasured 567 Unmeasured 624 Unmeasured Unmeasured Ta (° C.) Unmeasured616 Unmeasured 682 Unmeasured Unmeasured Ts (° C.) Unmeasured 865Unmeasured 957 Unmeasured Unmeasured 10⁴ dPa · s (° C.) Unmeasured 1,284Unmeasured 1,363 Unmeasured Unmeasured 10³ dPa · s (° C.) Unmeasured1,489 Unmeasured 1,562 Unmeasured Unmeasured 10^(2.5) dPa · s (° C.)Unmeasured 1,618 Unmeasured 1,689 Unmeasured Unmeasured TL (° C.)Unmeasured 1,040 Unmeasured 1,131 Unmeasured Unmeasured log₁₀η_(TL) (dPa· s) Unmeasured 5.7 Unmeasured 5.7 Unmeasured Unmeasured CS (MPa)Unmeasured 1,038 Unmeasured 1,203 Unmeasured Unmeasured DOL (μm)Unmeasured 29 Unmeasured 37 Unmeasured Unmeasured Fictive temperature (°C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) Unmeasured 22Unmeasured 43 Unmeasured Unmeasured Compatibility with Unmeasured xUnmeasured ∘ Unmeasured Unmeasured alumina

TABLE 19 Example No. 109 No. 110 No. 111 No. 112 No. 113 No. 114 GlassSiO₂ 61.7 60.7 59.7 60.4 59.4 59.1 composition Al₂O₃ 22.3 22.3 22.3 23.623.6 25.0 (mass %) B₂O₃ 0.0 1.0 2.0 0.0 1.0 0.0 Na₂O 13.5 13.5 13.5 13.513.5 13.4 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.230.21 0.20 0.21 0.20 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.44 Unmeasured 2.43 Unmeasured Unmeasured 2.45 α (×10⁻⁷) 79Unmeasured 78 Unmeasured Unmeasured 76 E Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) 666 Unmeasured 619Unmeasured Unmeasured 682 Ta (° C.) 725 Unmeasured 676 UnmeasuredUnmeasured 742 Ts (° C.) 1,003 Unmeasured 948 Unmeasured Unmeasured1,018 10⁴ dPa · s (° C.) 1,394 Unmeasured 1,343 Unmeasured Unmeasured1,387 10³ dPa · s (° C.) 1,586 Unmeasured 1,535 Unmeasured Unmeasured1,570 10^(2.5) dPa · s (° C.) 1,707 Unmeasured 1,655 UnmeasuredUnmeasured 1,680 TL (° C.) 1,194 Unmeasured 1,207 Unmeasured Unmeasured1,253 log₁₀η_(TL) (dPa · s) 5.5 Unmeasured 4.9 Unmeasured Unmeasured 5.0CS (MPa) 1,232 Unmeasured 1,213 Unmeasured Unmeasured 1,250 DOL (μm) 41Unmeasured 34 Unmeasured Unmeasured 37 Fictive temperature (° C.)Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) 37 Unmeasured 34Unmeasured Unmeasured 20 Compatibility with x Unmeasured x UnmeasuredUnmeasured Unmeasured alumina

TABLE 20 Example No. 115 No. 116 No. 117 No. 118 No. 119 No. 120 GlassSiO₂ 63.1 62.0 60.9 59.8 58.7 61.6 composition Al₂O₃ 19.4 19.4 19.4 19.419.4 21.0 (mass %) B₂O₃ 0.0 1.1 2.2 3.3 4.4 0.0 Na₂O 15.6 15.6 15.6 15.615.6 15.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.4 1.4 1.4 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.180.17 0.16 0.15 0.14 0.17 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.44 Unmeasured 2.44 Unmeasured 2.43 Unmeasured α (×10⁻⁷) 86Unmeasured 86 Unmeasured 86 Unmeasured E Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) 601 Unmeasured 570Unmeasured 554 Unmeasured Ta (° C.) 654 Unmeasured 617 Unmeasured 598Unmeasured Ts (° C.) 912 Unmeasured 857 Unmeasured 820 Unmeasured 10⁴dPa · s (° C.) 1,325 Unmeasured 1,286 Unmeasured 1,234 Unmeasured 10³dPa · s (° C.) 1,538 Unmeasured 1,498 Unmeasured 1,447 Unmeasured10^(2.5) dPa · s (° C.) 1,669 Unmeasured 1,631 Unmeasured 1,578Unmeasured TL (° C.) 1,011 Unmeasured 962 Unmeasured 888 Unmeasuredlog₁₀η_(TL) (dPa · s) 6.4 Unmeasured 6.4 Unmeasured 6.7 Unmeasured CS(MPa) 959 Unmeasured 972 Unmeasured 968 Unmeasured DOL (μm) 44Unmeasured 35 Unmeasured 31 Unmeasured Fictive temperature (° C.)Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Compatibilitywith ∘ Unmeasured ∘ Unmeasured ∘ Unmeasured alumina

TABLE 21 Example No. 121 No. 122 No. 123 No. 124 No. 125 No. 126 GlassSiO₂ 60.6 59.6 58.6 60.5 59.5 58.5 composition Al₂O₃ 21.0 21.0 21.0 22.322.3 22.3 (mass %) B₂O₃ 1.0 2.0 3.0 0.0 1.0 2.0 Na₂O 15.5 15.5 15.5 15.415.4 15.4 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.3 1.3 1.3 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.160.15 0.14 0.15 0.14 0.13 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.44 Unmeasured Unmeasured 2.44 Unmeasured 2.44 α (×10⁻⁷) 86Unmeasured Unmeasured 87 86 E Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Ps (° C.) 597 Unmeasured Unmeasured 646612 594 Ta (° C.) 650 Unmeasured Unmeasured 703 668 647 Ts (° C.) 910Unmeasured Unmeasured 969 936 908 10⁴ dPa · s (° C.) 1,322 UnmeasuredUnmeasured 1,369 1,336 1,316 10³ dPa · s (° C.) 1,525 UnmeasuredUnmeasured 1,565 1,536 1,514 10^(2.5) dPa · s (° C.) 1,654 UnmeasuredUnmeasured 1,687 1,658 1,636 TL (° C.) 1,002 Unmeasured Unmeasured 1,0501,067 1,000 log₁₀η_(TL) (dPa · s) 6.5 Unmeasured Unmeasured 6.6 6.1 6.5CS (MPa) 1,121 Unmeasured Unmeasured 1,235 1,169 1,208 DOL (μm) 39Unmeasured Unmeasured 47 40 38 Fictive temperature (° C.) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Dimensionalchange rate Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured (ppm) Crack generation rate (%) Unmeasured UnmeasuredUnmeasured 41 Unmeasured 48 Compatibility with ∘ Unmeasured Unmeasured ∘∘ ∘ alumina

TABLE 22 Example No. 127 No. 128 No. 129 No. 130 No. 131 No. 132 GlassSiO₂ 59.3 58.3 58.0 62.5 61.4 60.3 composition Al₂O₃ 23.6 23.6 25.0 19.419.4 19.4 (mass %) B₂O₃ 0.0 1.0 0.0 0.0 1.1 2.2 Na₂O 15.3 15.3 15.2 15.615.6 15.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.3 1.3 1.3 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.140.13 0.13 0.26 0.24 0.22 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured 2.45 2.44 Unmeasured 2.44 α (×10⁻⁷)Unmeasured Unmeasured 85 87 Unmeasured 87 E Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) Unmeasured 629 676608 Unmeasured 569 Ta (° C.) Unmeasured 686 736 661 Unmeasured 617 Ts (°C.) Unmeasured 957 1,010 914 Unmeasured 856 10⁴ dPa · s (° C.) 1,3841,357 1,388 1,314 Unmeasured 1,261 10³ dPa · s (° C.) 1,575 1,548 1,5721,520 Unmeasured 1,468 10^(2.5) dPa · s (° C.) 1,694 1,668 1,685 1,649Unmeasured 1,601 TL (° C.) 1,138 1,144 1,193 934 Unmeasured 929log₁₀η_(TL) (dPa · s) Unmeasured 5.6 5.5 7.3 Unmeasured 6.7 CS (MPa)1,244 1,256 1,334 1,057 Unmeasured 1,035 DOL (μm) 47 41 48 42 Unmeasured33 Fictive temperature (° C.) Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Dimensional change rate UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm) Crackgeneration rate (%) Unmeasured Unmeasured 44 Unmeasured Unmeasured 57Compatibility with ∘ Unmeasured ∘ ∘ Unmeasured ∘ alumina

TABLE 23 Example No. 133 No. 134 No. 135 No. 136 No. 137 No. 138 GlassSiO₂ 59.2 58.1 61.0 60.0 59.0 58.0 composition Al₂O₃ 19.4 19.4 21.0 21.021.0 21.0 (mass %) B₂O₃ 3.3 4.4 0.0 1.0 3.0 2.0 Na₂O 15.6 15.6 15.5 15.515.5 15.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.210.20 0.24 0.23 0.20 0.21 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured 2.44 2.44 2.44 2.44 2.44 α (×10⁻⁷) Unmeasured 85 8786 86 86 E Unmeasured Unmeasured 70 70 69 Unmeasured Ps (° C.)Unmeasured 553 626 604 574 585 Ta (° C.) Unmeasured 597 681 657 623 636Ts (° C.) Unmeasured 818 939 910 866 886 10⁴ dPa · s (° C.) Unmeasured1,217 1,331 1,307 1,279 1,278 10³ dPa · s (° C.) Unmeasured 1,423 1,5291,507 1,479 1,474 10^(2.5) dPa · s (° C.) Unmeasured 1,550 1,652 1,6301,603 1,595 TL (° C.) Unmeasured 921 1,046 1,029 973 989 log₁₀η_(TL)(dPa · s) Unmeasured 6.3 6.3 6.2 6.3 6.3 CS (MPa) Unmeasured 1,008 1,1851,226 1,133 1,140 DOL (μm) Unmeasured 29 43 37 32 36 Fictive temperature(° C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) Unmeasured 31Unmeasured Unmeasured Unmeasured Unmeasured Compatibility withUnmeasured ∘ Unmeasured x Unmeasured Unmeasured alumina

TABLE 24 Example No. 139 No. 140 No. 141 No. 142 No. 143 No. 144 GlassSiO₂ 59.8 58.8 57.8 58.6 57.6 57.3 composition Al₂O₃ 22.3 22.3 22.3 23.623.6 25.0 (mass %) B₂O₃ 0.0 1.0 2.0 0.0 1.0 0.0 Na₂O 15.4 15.4 15.4 15.315.3 15.2 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.230.21 0.20 0.21 0.20 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.45 Unmeasured 2.44 Unmeasured Unmeasured 2.46 α (×10⁻⁷) 86Unmeasured 85 Unmeasured Unmeasured 85 E Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) 641 Unmeasured 594Unmeasured Unmeasured 665 Ta (° C.) 697 Unmeasured 646 UnmeasuredUnmeasured 722 Ts (° C.) 957 Unmeasured 902 Unmeasured Unmeasured 98510⁴ dPa · s (° C.) 1,348 Unmeasured 1,300 Unmeasured Unmeasured 1,35910³ dPa · s (° C.) 1,542 Unmeasured 1,494 Unmeasured Unmeasured 1,53910^(2.5) dPa · s (° C.) 1,660 Unmeasured 1,612 Unmeasured Unmeasured1,652 TL (° C.) 1,077 Unmeasured 1,036 Unmeasured Unmeasured 1,150log₁₀η_(TL) (dPa · s) 6.2 Unmeasured 6.0 Unmeasured Unmeasured 5.7 CS(MPa) 1,281 Unmeasured 1,225 Unmeasured Unmeasured 1,377 DOL (μm) 42Unmeasured 35 Unmeasured Unmeasured 40 Fictive temperature (° C.)Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) 43 UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Compatibility with xUnmeasured x Unmeasured Unmeasured x alumina

TABLE 25 Example No. 145 No. 146 No. 147 No. 148 No. 149 No. 150 GlassSiO₂ 64.1 63.0 61.9 60.8 59.7 62.5 composition Al₂O₃ 19.4 19.4 19.4 19.419.4 21.0 (mass %) B₂O₃ 0.0 1.1 2.2 3.3 4.4 0.0 Na₂O 14.6 14.6 14.6 14.614.6 14.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.4 1.4 1.4 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.180.17 0.16 0.15 0.14 0.17 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.43 Unmeasured 2.43 Unmeasured 2.42 Unmeasured ured α (×10⁻⁷)Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured EUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Ps (°C.) 618 Unmeasured 582 Unmeasured 560 Unmeasured Ta (° C.) 674Unmeasured 633 Unmeasured 606 Unmeasured Ts (° C.) 942 Unmeasured 887Unmeasured 842 Unmeasured 10⁴ dPa · s (° C.) 1,362 Unmeasured 1,306Unmeasured 1,264 Unmeasured 10³ dPa · s (° C.) 1,572 Unmeasured 1,517Unmeasured 1,475 Unmeasured 10^(2.5) dPa · s (° C.) 1,705 Unmeasured1,649 Unmeasured 1,605 Unmeasured TL (° C.) 954 Unmeasured 912Unmeasured 911 Unmeasured log₁₀η_(TL) (dPa · s) 7.4 Unmeasured 7.3Unmeasured 6.7 Unmeasured CS (MPa) 1,005 Unmeasured 993 Unmeasured 981Unmeasured DOL (μm) 44 Unmeasured 36 Unmeasured 31 Unmeasured Fictivetemperature (° C.) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Dimensional change rate Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured (ppm) Crack generation rate(%) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredCompatibility with ∘ Unmeasured ∘ Unmeasured ∘ Unmeasured alumina

TABLE 26 Example No. 151 No. 152 No. 153 No. 154 No. 155 No. 156 GlassSiO₂ 61.5 60.5 59.5 61.4 60.4 59.4 composition Al₂O₃ 21.0 21.0 21.0 22.322.3 22.3 (mass %) B₂O₃ 1.0 2.0 3.0 0.0 1.0 2.0 Na₂O 14.6 14.6 14.6 14.514.5 14.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.3 1.3 1.3 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.160.15 0.14 0.15 0.14 0.13 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.43 Unmeasured Unmeasured 2.43 2.43 2.43 α (×10⁻⁷) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured E UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Ps (° C.) 612Unmeasured Unmeasured 658 627 607 Ta (° C.) 669 Unmeasured Unmeasured718 686 664 Ts (° C.) 939 Unmeasured Unmeasured 996 964 938 10⁴ dPa · s(° C.) 1,354 Unmeasured Unmeasured 1,395 1,371 1,347 10³ dPa · s (° C.)1,558 Unmeasured Unmeasured 1,591 1,568 1,544 10^(2.5) dPa · s (° C.)1,682 Unmeasured Unmeasured 1,709 1,690 1,669 TL (° C.) 982 UnmeasuredUnmeasured 1,130 1,136 1,105 log₁₀η_(TL) (dPa · s) 7.1 UnmeasuredUnmeasured 6.1 5.7 5.8 CS (MPa) 1,112 Unmeasured Unmeasured 1,191 1,2061,182 DOL (μm) 40 Unmeasured Unmeasured 47 42 38 Fictive temperature (°C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) UnmeasuredUnmeasured Unmeasured 65 Unmeasured 50 Compatibility with ∘ UnmeasuredUnmeasured ∘ Unmeasured ∘ alumina

TABLE 27 Example No. 157 No. 158 No. 159 No. 160 No. 161 No. 162 GlassSiO₂ 60.1 59.1 58.8 63.5 62.4 61.3 composition Al₂O₃ 23.6 23.6 25.0 19.419.4 19.4 (mass %) B₂O₃ 0.0 1.0 0.0 0.0 1.1 2.2 Na₂O 14.5 14.5 14.4 14.614.6 14.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.3 1.3 1.3 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.140.13 0.13 0.26 0.24 0.22 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) 2.44 Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured α(×10⁻⁷) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured E Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Ps (° C.) 673 639 687 623 Unmeasured 580 Ta (° C.) 33 698 748679 Unmeasured 631 Ts (° C.) 1,014 979 1,027 943 Unmeasured 883 10⁴ dPa· s (° C.) 1,410 1,369 1,402 1,347 Unmeasured 1,291 10³ dPa · s (° C.)1,600 1,558 1,584 1,552 Unmeasured 1,496 10^(2.5) dPa · s (° C.) 1,7161,680 1,698 1,680 Unmeasured 1,623 TL (° C.) 1,197 1,199 1,228 1,014Unmeasured 966 log₁₀η_(TL) (dPa · s) 5.6 5.2 5.3 6.7 Unmeasured 6.6 CS(MPa) 1,233 1,256 1,277 1,076 Unmeasured 1,035 DOL (μm) 47 41 45 42Unmeasured 34 Fictive temperature (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Dimensional change rateUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm)Crack generation rate (%) Unmeasured Unmeasured 27 Unmeasured UnmeasuredUnmeasured Compatibility with Unmeasured ∘ ∘ x Unmeasured x alumina

TABLE 28 Example No. 163 No. 164 No. 165 No. 166 No. 167 No. 168 GlassSiO₂ 60.2 59.1 61.9 60.9 59.9 58.9 composition Al₂O₃ 19.4 19.4 21.0 21.021.0 21.0 (mass %) B₂O₃ 3.3 4.4 0.0 1.0 2.0 3.0 Na₂O 14.6 14.6 14.6 14.614.6 14.6 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.210.20 0.24 0.23 0.21 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured 2.44 Unmeasured Unmeasured α(×10⁻⁷) Unmeasured Unmeasured Unmeasured 82 Unmeasured Unmeasured EUnmeasured Unmeasured Unmeasured 77 Unmeasured Unmeasured Ps (° C.)Unmeasured 561 Unmeasured 619 Unmeasured Unmeasured Ta (° C.) Unmeasured607 Unmeasured 675 Unmeasured Unmeasured Ts (° C.) Unmeasured 843Unmeasured 938 Unmeasured Unmeasured 10⁴ dPa · s (° C.) Unmeasured 1,250Unmeasured 1,335 Unmeasured Unmeasured 10³ dPa · s (° C.) Unmeasured1,455 Unmeasured 1,534 Unmeasured Unmeasured 10^(2.5) dPa · s (° C.)Unmeasured 1,583 Unmeasured 1,656 Unmeasured Unmeasured TL (° C.)Unmeasured 897 Unmeasured 1,076 Unmeasured Unmeasured log₁₀η_(TL) (dPa ·s) Unmeasured 6.9 Unmeasured 6.0 Unmeasured Unmeasured CS (MPa)Unmeasured 1,008 Unmeasured 1,276 Unmeasured Unmeasured DOL (μm)Unmeasured 29 Unmeasured 36 Unmeasured Unmeasured Fictive temperature (°C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredDimensional change rate Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured (ppm) Crack generation rate (%) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Compatibilitywith Unmeasured x Unmeasured x Unmeasured Unmeasured alumina

TABLE 29 Example No. 169 No. 170 No. 171 No. 172 No. 173 No. 174 GlassSiO₂ 60.7 59.7 58.7 59.4 58.4 58.1 composition Al₂O₃ 22.3 22.3 22.3 23.623.6 25.0 (mass %) B₂O₃ 0.0 1.0 2.0 0.0 1.0 0.0 Na₂O 14.5 14.5 14.5 14.514.5 14.4 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.230.21 0.20 0.21 0.20 0.20 (MgO + CaO + SrO + BaO/Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured α (×10⁻⁷) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Ta (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Ts (° C.) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured 10⁴ dPa · s (°C.) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured10³ dPa · s (° C.) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured 10^(2.5) dPa · s (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured TL (° C.) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured log₁₀η_(TL) (dPa· s) Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredCS (MPa) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured DOL (μm) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Fictive temperature (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Dimensional change rateUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm)Crack generation rate (%) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Compatibility with Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured alumina

TABLE 30 Example No. 175 No. 176 No. 177 No. 178 No. 179 No. 180 GlassSiO₂ 62.2 61.1 60.0 58.9 57.8 60.7 composition Al₂O₃ 19.4 19.4 19.4 19.419.4 21.0 (mass %) B₂O₃ 0.0 1.1 2.2 3.3 4.4 0.0 Na₂O 16.5 16.5 16.5 16.516.5 16.4 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.4 1.4 1.4 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.180.17 0.16 0.15 0.14 0.17 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured α (×10⁻⁷) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) 585 Unmeasured 559 Unmeasured 550Unmeasured Ta (° C.) 636 Unmeasured 604 Unmeasured 592 Unmeasured Ts (°C.) 884 Unmeasured 834 Unmeasured 802 Unmeasured 10⁴ dPa · s (° C.)1,289 Unmeasured 1,243 Unmeasured 1,215 Unmeasured 10³ dPa · s (° C.)1,500 Unmeasured 1,456 Unmeasured 1,427 Unmeasured 10^(2.5) dPa · s (°C.) 1,632 Unmeasured 1,589 Unmeasured 1,558 Unmeasured TL (° C.) 976Unmeasured 946 Unmeasured <900 Unmeasured log₁₀η_(TL) (dPa · s) 6.5Unmeasured 6.2 Unmeasured >6.4 Unmeasured CS (MPa) 867 Unmeasured 913Unmeasured 930 Unmeasured DOL (μm) 43 Unmeasured 34 Unmeasured 30Unmeasured Fictive temperature (° C.) Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Dimensional change rate UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm) Crackgeneration rate (%) 68 Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Compatibility with ∘ Unmeasured ∘ Unmeasured ∘ Unmeasuredalumina

TABLE 31 Example No. 181 No. 182 No. 183 No. 184 No. 185 No. 186 GlassSiO₂ 59.7 58.7 57.7 59.6 58.6 57.6 composition Al₂O₃ 21.0 21.0 21.0 22.322.3 22.3 (mass %) B₂O₃ 1.0 2.0 3.0 0.0 1.0 2.0 Na₂O 16.4 16.4 16.4 16.316.3 16.3 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.4 1.4 1.4 1.3 1.3 1.3 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.160.15 0.14 0.15 0.14 0.13 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured α (×10⁻⁷) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) 583 Unmeasured Unmeasured 627 598 582 Ta(° C.) 633 Unmeasured Unmeasured 681 651 633 Ts (° C.) 881 UnmeasuredUnmeasured 940 906 882 10⁴ dPa · s (° C.) 1,287 Unmeasured Unmeasured1,339 1,309 1,287 10³ dPa · s (° C.) 1,493 Unmeasured Unmeasured 1,5381,508 1,487 10^(2.5) dPa · s (° C.) 1,619 Unmeasured Unmeasured 1,6641,635 1,611 TL (° C.) 956 Unmeasured Unmeasured 1,069 1,058 1,006log₁₀η_(TL) (dPa · s) 6.7 Unmeasured Unmeasured 6.1 5.9 6.1 CS (MPa)1,009 Unmeasured Unmeasured 1,144 1,131 1,095 DOL (μm) 39 UnmeasuredUnmeasured 45 40 38 Fictive temperature (° C.) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Dimensional change rateUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured (ppm)Crack generation rate (%) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Compatibility with ∘ Unmeasured Unmeasured ∘ ∘Unmeasured alumina

TABLE 32 Example No. 187 No. 188 No. 189 No. 190 No. 191 No. 192 GlassSiO₂ 58.4 57.4 57.1 61.6 60.5 59.4 composition Al₂O₃ 23.6 23.6 25.0 19.419.4 19.4 (mass %) B₂O₃ 0.0 1.0 0.0 0.0 1.1 2.2 Na₂O 16.2 16.2 16.1 16.516.5 16.5 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 1.3 1.3 1.3 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.140.13 0.13 0.26 0.24 0.22 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured α (×10⁻⁷) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) 646 614 663 593 Unmeasured 561 Ta (° C.)702 669 721 644 Unmeasured 607 Ts (° C.) 965 931 985 889 Unmeasured 83710⁴ dPa · s (° C.) 1,353 1,325 1,368 1,286 Unmeasured 1,236 10³ dPa · s(° C.) 1,544 1,518 1,553 1,491 Unmeasured 1,442 10^(2.5) dPa · s (° C.)1,662 1,638 1,666 1,618 Unmeasured 1,569 TL (° C.) 1,123 1,055 1,1501,006 Unmeasured <900 log₁₀η_(TL) (dPa · s) 5.8 6.1 5.7 6.2Unmeasured >6.8 CS (MPa) 1,236 1,206 1,341 967 Unmeasured 993 DOL (μm)46 42 46 42 Unmeasured 31 Fictive temperature (° C.) UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Dimensionalchange rate Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured (ppm) Crack generation rate (%) Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Compatibility withUnmeasured ∘ Unmeasured Unmeasured Unmeasured ∘ alumina

TABLE 33 Example No. 193 No. 194 No. 195 No. 196 No. 197 No. 198 GlassSiO₂ 58.3 57.2 60.1 59.1 58.1 57.1 composition Al₂O₃ 19.4 19.4 21.0 21.021.0 21.0 (mass %) B₂O₃ 3.3 4.4 0.0 1.0 2.0 3.0 Na₂O 16.5 16.5 16.4 16.416.4 16.4 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.210.20 0.24 0.23 0.21 0.20 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured 2.45 2.45 Unmeasured Unmeasured α (×10⁻⁷)Unmeasured Unmeasured 89 89 Unmeasured Unmeasured E UnmeasuredUnmeasured 70 70 Unmeasured Unmeasured Ps (° C.) Unmeasured 548 615 590Unmeasured Unmeasured Ta (° C.) Unmeasured 590 667 640 UnmeasuredUnmeasured Ts (° C.) Unmeasured 802 914 884 Unmeasured Unmeasured 10⁴dPa · s (° C.) Unmeasured 1,195 1,301 1,275 Unmeasured Unmeasured 10³dPa · s (° C.) Unmeasured 1,401 1,501 1,475 Unmeasured Unmeasured10^(2.5) dPa · s (° C.) Unmeasured 1,529 1,624 1,597 UnmeasuredUnmeasured TL (° C.) Unmeasured <900 1,063 1,004 Unmeasured Unmeasuredlog₁₀η_(TL) (dPa · s) Unmeasured >6.3 5.8 6.1 Unmeasured Unmeasured CS(MPa) Unmeasured 982 1,153 1,152 Unmeasured Unmeasured DOL (μm)Unmeasured 27 43 38 Unmeasured Unmeasured Fictive temperature UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured (° C.)Dimensional change Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured rate (ppm) Crack generation Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured rate (%) Compatibility withUnmeasured ∘ Unmeasured Unmeasured Unmeasured Unmeasured alumina

TABLE 34 Example No. 199 No. 200 No. 201 No. 202 No. 203 No. 204 GlassSiO₂ 58.9 57.9 56.9 57.7 56.7 56.4 composition Al₂O₃ 22.3 22.3 22.3 23.623.6 25.0 (mass %) B₂O₃ 0.0 1.0 2.0 0.0 1.0 0.0 Na₂O 16.3 16.3 16.3 16.216.2 16.1 K₂O 0.0 0.0 0.0 0.0 0.0 0.0 MgO 2.0 2.0 2.0 2.0 2.0 2.0 CaO0.0 0.0 0.0 0.0 0.0 0.0 SnO₂ 0.5 0.5 0.5 0.5 0.5 0.5 Molar ratio 0.230.21 0.20 0.21 0.20 0.20 (MgO + CaO + SrO + BaO/ Al₂O₃ + B₂O₃) Density(g/cm³) Unmeasured Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured α (×10⁻⁷) Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured E Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured Ps (° C.) 627 Unmeasured Unmeasured Unmeasured 612Unmeasured Ta (° C.) 681 Unmeasured Unmeasured Unmeasured 665 UnmeasuredTs (° C.) 935 Unmeasured Unmeasured Unmeasured 919 Unmeasured 10⁴ dPa ·s (° C.) 1,321 Unmeasured 1,263 Unmeasured 1,297 Unmeasured 10³ dPa · s(° C.) 1,516 Unmeasured 1,457 Unmeasured 1,484 Unmeasured 10^(2.5) dPa ·s (° C.) 1,636 Unmeasured 1,577 Unmeasured 1,597 Unmeasured TL (° C.)1,085 Unmeasured 1,044 Unmeasured 1,100 Unmeasured log₁₀η_(TL) (dPa · s)5.8 Unmeasured Unmeasured Unmeasured 5.5 Unmeasured CS (MPa) 1,199Unmeasured 1,144 Unmeasured 1,269 Unmeasured DOL (μm) 42 Unmeasured 34Unmeasured 37 Unmeasured Fictive temperature Unmeasured UnmeasuredUnmeasured Unmeasured Unmeasured Unmeasured (° C.) Dimensional changeUnmeasured Unmeasured Unmeasured Unmeasured Unmeasured Unmeasured rate(ppm) Crack generation Unmeasured Unmeasured Unmeasured UnmeasuredUnmeasured Unmeasured rate (%) Compatibility with ∘ Unmeasured ∘Unmeasured x Unmeasured alumina

Each of the samples in the tables was produced as described below. Foreach of the samples shown in Tables 1 to 8, glass raw materials wereblended so as to have the glass composition in the tables, and melted at1,600° C. for 8 hours using a platinum pot. After that, the resultantmolten glass was poured onto a carbon sheet so as to be formed into asheet shape. In addition, for each of the samples shown in Tables 9 to34, glass raw materials were blended so as to have the glass compositionin the tables, and melted at 1,600° C. for 21 hours using a platinumpot. After that, the resultant molten glass was poured onto a carbonsheet so as to be formed into a sheet shape. The obtained glass sheetswere evaluated for various characteristics.

The density ρ is a value obtained through measurement by a knownArchimedes method.

The thermal expansion coefficient α is a value obtained throughmeasurement of an average thermal expansion coefficient in a temperaturerange of from 25 to 380° C. using a dilatometer.

The Young's modulus E is a value obtained through measurement by awell-known resonance method.

The strain point Ps and the annealing point Ta are values obtainedthrough measurement based on a method of ASTM C336.

The softening point Ts is a value obtained through measurement based ona method of ASTM C338.

The temperatures at the viscosities at high temperature of 10^(4.0)dPa·s, 10^(3.0) dPa·s, and 10^(2.5) dPa·s are values obtained throughmeasurement by a platinum sphere pull up method.

The liquidus temperature TL is a value obtained through measurement of atemperature at which crystals of glass are deposited after glass powderthat passes through a standard 30-mesh sieve (sieve opening: 500 μm) andremains on a 50-mesh sieve (sieve opening: 300 μm) is placed in aplatinum boat and then kept for 24 hours in a gradient heating furnace.

The liquidus viscosity is a value obtained through measurement of aviscosity of glass at the liquidus temperature by a platinum sphere pullup method.

The crack generation rate was measured as described below. First, in aconstant temperature and humidity chamber kept at a humidity of 30% anda temperature of 25° C., a Vickers indenter set to a load of 1,000 gf isdriven into a glass surface (optically polished surface) for 15 seconds,and 15 seconds after that, the number of cracks generated from the fourcorners of the indentation is counted (4 per indentation at maximum).The indenter was driven in this manner 20 times, the total number ofgenerated cracks was determined, and then the crack generation rate wasdetermined by the following expression: total number of generatedcracks/80×100.

The compatibility with alumina was evaluated as described below. Each ofthe samples having a viscosity of 10^(4.5) dPa·s was brought intocontact with alumina for 48 hours. After that, a contact interfacebetween each of the samples and alumina was observed, an evaluation wasmade by marking a case where no devitrified crystal is precipitated withSymbol “∘”, and marking a case where a devitrified crystal isprecipitated with Symbol “x”.

As apparent from Tables 1 to 34, each of Samples Nos. 1 to 204 has adensity of 2.54 g/cm³ or less and a thermal expansion coefficient offrom 88 to 100×10⁻⁷/° C., thus being suitable as a material for atempered glass, that is, a glass to be tempered. In addition, each ofthe samples has a liquidus viscosity of 10^(4.4) dPa·s or more, andhence can be formed into a sheet shape by an overflow down-draw method.Moreover, each of the samples has a temperature at 10^(2.5) dPa·s of1,738° C. or less, and hence is considered to allow the production of aglass sheet in a large amount at low cost with high productivity. Itshould be noted that the glass composition in the surface layer of theglass differs microscopically between before and after temperingtreatment, but when the glass is observed as a whole, the glasscomposition does not differ substantially.

Next, both surfaces of each of the samples shown in Tables 1 to 8 weresubjected to optical polishing. After that, each of the samples wassubjected to ion exchange treatment by being immersed in a KNO₃ moltensalt (fresh KNO₃ molten salt) at 440° C. for 6 hours. In addition, bothsurfaces of each of the samples shown in Tables 9 to 34 were subjectedto optical polishing. After that, each of the samples was subjected toion exchange treatment by being immersed in a KNO₃ molten salt (freshKNO₃ molten salt) at 430° C. for 4 hours. The surfaces of each of thesamples were washed after the ion exchange treatment. Subsequently, thecompression stress value (CS) and thickness (DOL) of the compressionstress layer in the surfaces were calculated on the basis of the numberof interference fringes observed using a surface stress meter (FSM-6000manufactured by TOSHIBA CORPORATION) and intervals therebetween. In thecalculation, the refractive index and optical elastic constant of eachof the samples were defined as 1.51 and 30 [(nm/cm)/MPa], respectively.

As apparent from Tables 1 to 34, when each of the samples was subjectedto ion exchange treatment in a fresh KNO₃ molten salt, the compressionstress layer in a surface thereof had a compression stress value of 823MPa or more and a thickness of 27 μm or more.

Example 2

Glass raw materials were blended so as to have the glass composition ofSample No. 39 shown in Table 7, melted, and fined. After that, theresultant molten glass was formed into a sheet shape by an overflowdown-draw method to obtain a glass sheet having a sheet thickness of 0.7mm. The obtained glass sheet was measured for its fictive temperatureTf. The measurement method for the fictive temperature Tf is describedbelow. A sample is kept at a temperature equal to or higher than itsstrain point for 24 hours, then rapidly cooled by being immediatelybrought into contact with a metal sheet, and measured for itsdimensional change. When the sample is kept at a temperature T1 higherthan the fictive temperature Tf, the dimensional change shows a positivevalue ΔL1, and when the sample is kept at a temperature T2 lower thanthe fictive temperature Tf, the dimensional change shows a negativevalue ΔL2. In the case where T1-T2 is from 0 to 20° C., the Tf can bedetermined by the following equation: Tf=(T2×ΔL1−T1×ΔL2)/(ΔL1−ΔL2). Inaddition, the obtained glass sheet was subjected to ion exchangetreatment by being immersed in a KNO₃ molten salt (KNO₃ molten salthaving no history of being used) at 440° C. for 6 hours. As a result, asshown in the table, the obtained glass sheet had a fictive temperatureTf of 651° C. and a dimensional change rate S between before and aftertempering treatment of 525 ppm. It should be noted that when each ofSamples Nos. 1 to 38 and 40 to 204 of Tables 1 to 34 is similarlyevaluated, the glass sheet to be obtained is considered to have afictive temperature Tf of 550° C. or more and a dimensional change rateS between before and after tempering treatment of 1,000 ppm or less.

INDUSTRIAL APPLICABILITY

The tempered glass and tempered glass sheet of the present invention aresuitable for a cover glass of a cellular phone, a digital camera, a PDA,or the like, or a glass substrate for a touch panel display or the like.Further, the tempered glass and tempered glass sheet of the presentinvention can be expected to find use in applications requiring highmechanical strength, for example, a window glass, a substrate for amagnetic disk, a substrate for a flat panel display, a cover glass for asolar battery, a cover glass for a solid image pick-up element, andtableware, in addition to the above-mentioned applications.

1. A tempered glass having a compressive stress layer in a surfacethereof, comprising as a glass composition, in terms of mass %, 50 to80% of SiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, and 5to 25% of Na₂O, and being substantially free of As₂O₃, Sb₂O₃, PbO, andF.
 2. The tempered glass according to claim 1, wherein the temperedglass comprises as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than7.0 to 25% of Na₂O, and 0 to 2% of SrO.
 3. The tempered glass accordingto claim 1, wherein the tempered glass comprises as a glass composition,in terms of mass %, 50 to 76% of SiO₂, more than 16.0 to 30% of Al₂O₃, 0to 6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0 to 25% of Na₂O, 0 to 2%of SrO, and 0 to 4.5% of TiO₂.
 4. The tempered glass according to claim1, wherein the tempered glass comprises as a glass composition, in termsof mass %, 50 to 76% of SiO₂, more than 16.0 to 30% of Al₂O₃, 0 to 6% ofB₂O₃, 0 to 1.7% of Li₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0to 0.5% of TiO₂, and 0 to 4% of ZrO₂.
 5. The tempered glass according toclaim 1, wherein the tempered glass comprises as a glass composition, interms of mass %, 50 to 76% of SiO₂, more than 16.0 to 30% of Al₂O₃, 0 to6% of B₂O₃, 0 to 1.7% of Li₂O, more than 7.0 to 25% of Na₂O, 0 to 2% ofSrO, 0 to 0.5% of TiO₂, 0 to 4% of ZrO₂, and 0 to 1% of P₂O₅, and has amolar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.60.
 6. Thetempered glass according to claim 1, wherein the tempered glasscomprises as a glass composition, in terms of mass %, 50 to 76% of SiO₂,more than 16.0 to 30% of Al₂O₃, 0 to 6% of B₂O₃, O to less than 1.0% ofLi₂O, more than 7.0 to 25% of Na₂O, 0 to 2% of SrO, 0 to 0.5% of TiO₂, 0to 2% of ZrO₂, 0.2 to 3% of SnO₂, and 0 to 1% of P₂O₅, and has a molarratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.55.
 7. The temperedglass according to claim 1, wherein the tempered glass comprises as aglass composition, in terms of mass %, 50 to 73% of SiO₂, more than 16.0to 30% of Al₂O₃, 0 to 6% of B₂O₃, O to less than 1.0% of Li₂O, more than7.0 to 25% of Na₂O, 10 to 30% of Li₂O+Na₂O+K₂O, 0 to 4% of CaO, 0 to 2%of SrO, 0 to 0.5% of TiO₂, 0 to 2% of ZrO₂, 0.2 to 3% of SnO₂, and 0 to1% of P₂O₅, and has a molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from0 to 0.55.
 8. The tempered glass according to claim 1, wherein acompression stress value of the compression stress layer is 300 MPa ormore and 1,200 MPa or less, and a thickness of the compression stresslayer is 10 μm or more and 60 μm or less.
 9. The tempered glassaccording to claim 1, wherein the tempered glass has a liquidustemperature of 1,200° C. or less.
 10. The tempered glass according toclaim 1, wherein the tempered glass has a liquidus viscosity of 10^(4.0)dPa·s or more.
 11. The tempered glass according to claim 1, wherein thetempered glass has a temperature at 10^(4.0) dPa·s of 1,300° C. or less.12. The tempered glass according to claim 1, wherein the tempered glasshas a thermal expansion coefficient in a temperature range of from 25 to380° C. of 100×10⁻⁷/° C. or less.
 13. A tempered glass sheet, comprisingthe tempered glass according to claim
 1. 14. A tempered glass sheethaving a length dimension of 500 mm or more, a width dimension of 300 mmor more, and a thickness of from 0.5 to 2.0 mm, having a compressionstress value of a compression stress layer of 300 MPa or more and 1,200MPa or less and a thickness of the compression stress layer of 10 μm ormore and 60 μm or less, and being subjected to tempering treatment so asto have a dimensional change rate S between before and after temperingtreatment of from −1,000 ppm to +1,000 ppm.
 15. The tempered glass sheetaccording to claim 13, wherein the tempered glass sheet has a Young'smodulus of 65 GPa or more.
 16. The tempered glass sheet according toclaim 13, wherein the tempered glass sheet has a fictive temperature Tfof 500° C. or more.
 17. The tempered glass sheet according to claim 13,wherein the tempered glass sheet is formed by an overflow down-drawmethod.
 18. The tempered glass sheet according to claim 17, wherein thetempered glass sheet is cut at a position spaced apart downwardly by1,000 mm or more from a lower end of a forming trough used in theoverflow down-draw method.
 19. The tempered glass sheet according toclaim 13, wherein the tempered glass sheet is used for a touch paneldisplay.
 20. The tempered glass sheet according to claim 13, wherein thetempered glass sheet is used for a cover glass for a cellular phone. 21.The tempered glass sheet according to claim 13, wherein the temperedglass sheet is used for a cover glass for a solar battery.
 22. Thetempered glass sheet according to claim 13, wherein the tempered glasssheet is used for a protective member for a display.
 23. A temperedglass sheet having a length dimension of 500 mm or more, a widthdimension of 300 mm or more, and a thickness of from 0.3 to 2.0 mm,comprising as a glass composition, in terms of mass %, 50 to 80% ofSiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to 2% of Li₂O, 5 to 25% ofNa₂O, 10 to 30% of Li₂O+Na₂O+K₂O, 0 to 2% of SrO, 0 to less than 0.50%of TiO₂, 0 to 4% of ZrO₂, 0.2 to 3% of SnO₂, and 0 to 1% of P₂O₅, havinga molar ratio (MgO+CaO+SrO+BaO)/(Al₂O₃+B₂O₃) of from 0 to 0.60, beingsubstantially free of As₂O₃, Sb₂O₃, PbO, and F, having a compressionstress value of a compression stress layer of 300 MPa or more and 1,200MPa or less, a thickness of the compression stress layer of 10 μm ormore and 60 μm or less, a liquidus temperature of 1,200° C. or less, athermal expansion coefficient in a temperature range of from 25 to 380°C. of 100×10⁻⁷ or less, a Young's modulus of 65 GPa or more, and afictive temperature Tf of 500° C. or more, and being subjected totempering treatment so as to have a dimensional change rate S betweenbefore and after tempering treatment of from −1,000 ppm to +1,000 ppm.24. A glass to be tempered, comprising as a glass composition, in termsof mass %, 50 to 80% of SiO₂, 10 to 30% of Al₂O₃, 0 to 6% of B₂O₃, 0 to2% of Li₂O, and 5 to 25% of Na₂O, and being substantially free of As₂O₃,Sb₂O₃, PbO, and F.
 25. A glass to be tempered having a dimensionalchange rate S between before and after tempering treatment of from−1,000 ppm to +1,000 ppm, the tempering treatment comprising immersionin a KNO₃ molten salt at 440° C. for 6 hours.
 26. The glass to betempered according to claim 25, wherein the glass to be tempered has afictive temperature Tf of 500° C. or more.